MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Analytica Chimica Acta' source. Thu, 09 Feb 2012 13:01:25 +0100 http://www.medworm.com/index.php?rid=5619272&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244132%26dopt%3DAbstract Authors: Sánchez P, Alberts D, Fernández B, Menéndez A, Pereiro R, Sanz-Medel A Abstract During the last decade the photovoltaic industry has been growing rapidly. One major strategy to reduce the production costs is the use of thin film solar cells based on hydrogenated amorphous silicon (a-Si:H). The potential of pulsed radiofrequency glow discharge coupled to optical emission spectrometry (rf-PGD-OES) for the analysis of such type of materials has been investigated in this work. It is known that when hydrogen is present in the argon discharge, even in small quantities, significant changes can occur in the emission intensities and sputtering rates measured. Therefore, a critical comparison has been carried out by rf-PGD-OES, in terms of emission intensities, penetration rates ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619272 Mon, 23 Jan 2012 01:16:28 +0100 5619272 http://www.medworm.com/index.php?rid=5619271&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244133%26dopt%3DAbstract Authors: Melchert WR, Reis BF, Rocha FR Abstract Flow analysis has achieved its majority as a well-established tool to solve analytical problems. Evolution of flow-based approaches has been analyzed by diverse points of view, including historical aspects, the commutation concept and the impact on analytical methodologies. In this overview, the evolution of flow analysis towards green analytical chemistry is demonstrated by comparing classical procedures implemented with different flow approaches. The potential to minimize reagent consumption and waste generation and the ability to implement processes unreliable in batch to replace toxic chemicals are also emphasized. Successful applications of greener approaches in flow analysis are also discussed, focusing on the last 10 years. ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619271 Mon, 23 Jan 2012 01:16:18 +0100 5619271 http://www.medworm.com/index.php?rid=5619270&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244134%26dopt%3DAbstract Authors: Pino V, Afonso AM Abstract Ionic liquids (ILs) are a class of ionic, nonmolecular solvents which remain in liquid state at temperatures below 100°C. ILs possess a variety of properties including low to negligible vapor pressure, high thermal stability, miscibility with water or a variety of organic solvents, and variable viscosity. IL-modified silica as novel high-performance liquid chromatography (HPLC) stationary phases have attracted considerable attention for their differential behavior and low free-silanol activity. Indeed, around 21 surface-confined ionic liquids (SCIL) stationary phases have been developed in the last six years. Their chromatographic behavior has been studied, and, despite the presence of a positive charge on the stationary phase, they showed consi... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619270 Mon, 23 Jan 2012 01:16:09 +0100 5619270 http://www.medworm.com/index.php?rid=5619269&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244135%26dopt%3DAbstract Authors: García-Salgado S, Quijano MA, Bonilla MM Abstract Twelve commercially available edible marine algae from France, Japan and Spain and the certified reference material (CRM) NIES No. 9 Sargassum fulvellum were analyzed for total arsenic and arsenic species. Total arsenic concentrations were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) after microwave digestion and ranged from 23 to 126μgg(-1). Arsenic species in alga samples were extracted with deionized water by microwave-assisted extraction and showed extraction efficiencies from 49 to 98%, in terms of total arsenic. The presence of eleven arsenic species was studied by high performance liquid chromatography-ultraviolet photo-oxidation-hydride generation atomic-fluorescence spectrometry... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619269 Mon, 23 Jan 2012 01:15:59 +0100 5619269 http://www.medworm.com/index.php?rid=5619268&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244136%26dopt%3DAbstract Authors: Bouabidi A, Ziemons E, Marini R, Hubert C, Talbi M, Bouklouze A, Bourichi H, Karbane ME, Boulanger B, Hubert P, Rozet E Abstract Analytical methods capability evaluation can be a useful methodology to assess the fitness of purpose of these methods for their future routine application. However, care on how to compute the capability indices have to be made. Indeed, the commonly used formulas to compute capability indices such as Cpk, will highly overestimate the true capability of the methods. Especially during methods validation or transfer, there are only few experiments performed and, using in these situations the commonly applied capability indices to declare a method as valid or as transferable to a receiving laboratory will conduct to inadequate decisions. In this work... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619268 Mon, 23 Jan 2012 01:15:49 +0100 5619268 http://www.medworm.com/index.php?rid=5619267&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244137%26dopt%3DAbstract In this study, samples from three different muscles (semitendinosus (ST), semimembranosus (SM), longissimus dorsi (LD)) originated from Texel, Suffolk, Scottish Blackface and Charollais breeds were collected and used for image acquisition and quality measurements. Hyperspectral images were acquired using a pushbroom NIR hyperspectral imaging system in the spectral range of 900-1700nm. A partial least-squares (PLS) regression, as a multivariate calibration method, was used to correlate the NIR reflectance spectra with quality values of the tested muscles. The models performed well for predicting pH, colour and drip loss with the coefficient of determination (R(2)) of 0.65, 0.91 and 0.77, respectively. Image processing algorithm was also developed to transfer the predictive model in every pi... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619267 Mon, 23 Jan 2012 01:15:38 +0100 5619267 http://www.medworm.com/index.php?rid=5619266&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244138%26dopt%3DAbstract Authors: Mikuška P, Večeřa Z, Bartošíková A, Maenhaut W Abstract A specially designed annular diffusion denuder for simultaneous removal of organic gaseous compounds and atmospheric oxidants in carbonaceous aerosol sampling is presented. Various kinds of denuder coatings were compared with respect to the collection efficiency of both organic gaseous compounds and NO(2) and ozone. The optimum sorbent is a mixture of activated charcoal and sulfite on molecular sieve. To ensure high collection efficiency over long-term field operation, two annular diffusion denuders are combined in series. The first half of the first denuder is filled with Na(2)SO(3) on molecular sieve (23cm long layer) while the second half of the first denuder and the whole second denuder are filled with activ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619266 Mon, 23 Jan 2012 01:15:29 +0100 5619266 http://www.medworm.com/index.php?rid=5619265&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244139%26dopt%3DAbstract Authors: Jiménez-Soto JM, Cárdenas S, Valcárcel M Abstract A new dispersive micro solid-phase extraction method which uses single-walled carbon nanohorns (SWNHs) as sorbent is proposed. The procedure combines the excellent sorbent properties of the nanoparticles with the efficiency of the dispersion of the material in the sample matrix. Under these conditions, the interaction with the analytes is maximized. The determination of polycyclic aromatic hydrocarbons was selected as model analytical problem. Two dispersion strategies were evaluated, being the functionalization via microwave irradiation better than the use of a surfactant. The extraction was accomplished by adding 1mL of oxidized SWHNs (o-SWNHs) dispersion to 10mL of water sample. After extraction, the mixture was passe... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619265 Mon, 23 Jan 2012 01:15:20 +0100 5619265 http://www.medworm.com/index.php?rid=5619264&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244140%26dopt%3DAbstract Authors: Najafi NM, Tavakoli H, Abdollahzadeh Y, Alizadeh R Abstract Herein, ultrasound-assisted emulsification microextraction (USAEME) and dispersive liquid-liquid microextraction (DLLME) methods based on applying low-density organic solvents have been critically compared for the speciation of inorganic selenium, Se(IV) (selenite) and Se(VI) (selenate) in environmental water samples by gas chromatography-flame ionization detection (GC-FID). At pH 2 and T=75°C for 7min, only Se(IV) was able to form the piazselenol complex with 4-nitro-o-phenylenediamine. Piazselenol was extracted using an extraction solvent and was injected into a GC-FID instrument for the determination of Se(IV). Conveniently, Se(VI) remained in the aqueous phase. Total inorganic selenium was determined after th... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619264 Mon, 23 Jan 2012 01:15:10 +0100 5619264 http://www.medworm.com/index.php?rid=5619263&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244141%26dopt%3DAbstract Authors: Khalili-Fard V, Ghanemi K, Nikpour Y, Fallah-Mehrjardi M Abstract The application of sulfur microparticles as efficient adsorbents for the solid-phase extraction (SPE) and determination of trace amounts of 10 polycyclic aromatic hydrocarbons (PAHs) was investigated in sea water and wastewater samples using high performance liquid chromatography coupled with an ultraviolet detector (HPLC-UV). Parameters influencing the preconcentration of PAHs such as the amount of sulfur, solution flow rate and volume, elution solvent, type and concentration of organic modifier, and salt effect were examined. The results showed that at a flow rate of 10mLmin(-1) for the sample solutions (100mL), the PAHs could be adsorbed on the sulfur microparticles and then eluted by 2.0mL of acetonitril... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619263 Mon, 23 Jan 2012 01:15:01 +0100 5619263 http://www.medworm.com/index.php?rid=5619262&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244142%26dopt%3DAbstract In conclusion, treatment of different standards (e.g., between the same or different phases) will inevitably induce biases in most VOCs, although certain volatiles (e.g., benzene, MIBK, etc.) are virtually unaffected by such variables in a practical sense. PMID: 22244142 [PubMed - in process] (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619262 Mon, 23 Jan 2012 01:14:52 +0100 5619262 http://www.medworm.com/index.php?rid=5619261&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244143%26dopt%3DAbstract Authors: Hertz R, Streibel T, Liu C, McAdam K, Zimmermann R Abstract A microprobe sampling device (μ-probe) has been developed for in situ on-line photo ionization mass spectrometric analysis of volatile chemical species formed within objects consisting of organic matter during thermal processing. With this approach the chemical signature occurring during heating, pyrolysis, combustion, roasting and charring of organic material within burning objects such as burning fuel particles (e.g., biomass or coal pieces), lit cigarettes or thermally processed food products (e.g., roasting of coffee beans) can be investigated. Due to its dynamic changes between combustion and pyrolysis phases the cigarette smoking process is particularly interesting and has been chosen as first application. ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619261 Mon, 23 Jan 2012 01:14:42 +0100 5619261 http://www.medworm.com/index.php?rid=5619260&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244144%26dopt%3DAbstract Authors: Shimomura T, Sumiya T, Ono M, Ito T, Hanaoka TA Abstract A novel amperometric biosensor for the measurement of l-lactate has been developed. The device comprises a screen-printed carbon electrode containing cobalt phthalocyanine (CoPC-SPCE), coated with lactate oxidase (LOD) that is immobilized in mesoporous silica (FSM8.0) using a polymer matrix of denatured polyvinyl alcohol; a Nafion layer on the electrode surface acts as a barrier to interferents. The sampling unit attached to the SPCE requires only a small sample volume of 100μL for each measurement. The measurement of l-lactate is based on the signal produced by hydrogen peroxide, the product of the enzymatic reaction. The behavior of the biosensor, LOD-FSM8.0/Naf/CoPC-SPCE, was examined in terms of pH, applied pote... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619260 Mon, 23 Jan 2012 01:14:33 +0100 5619260 http://www.medworm.com/index.php?rid=5619259&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244145%26dopt%3DAbstract Authors: Terborg L, Nowak S, Passerini S, Winter M, Karst U, Haddad PR, Nesterenko PN Abstract In this work, hydrolysis of three different hexafluorophosphate salts in purified water was investigated. Aqueous samples of lithium hexafluorophosphate (LiPF(6)), sodium hexafluorophosphate (NaPF(6)) and potassium hexafluorophosphate (KPF(6)) were prepared and stored for different times. Ion chromatography (IC) with UV as well as non-suppressed and suppressed conductivity detection was used for the analysis of the reaction products. For the detection and identification of the formed decomposition products, an IC method using IonPac AS14A 250mm×4.0mm i.d. column and 2.5mM KHCO(3)-2.5mM K(2)CO(3) eluent was established. Besides hexafluorophosphate, four other anionic species were detected... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619259 Mon, 23 Jan 2012 01:14:24 +0100 5619259 http://www.medworm.com/index.php?rid=5619258&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244146%26dopt%3DAbstract This study demonstrates the applicability of DPI to monitor the process of SLB formation; and our findings, obtained by both DPI and CE, confirm that the presence of the SLB reduced drastically the problematic interactions between cationic, alkaline proteins and the negatively charged silica capillary wall, leading to better recovery and efficient separation of the proteins under investigation. PMID: 22244146 [PubMed - in process] (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619258 Mon, 23 Jan 2012 01:14:15 +0100 5619258 http://www.medworm.com/index.php?rid=5619257&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244163%26dopt%3DAbstract This article provides a review of how functionally modified gold colloids are applied in the detection of a broad range of threat agents, including radioactive substances, explosive compounds, chemical warfare agents, biotoxins, and biothreat pathogens through any of the four sensory means mentioned previously. PMID: 22244163 [PubMed - in process] (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619257 Mon, 23 Jan 2012 01:14:06 +0100 5619257 http://www.medworm.com/index.php?rid=5619256&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244164%26dopt%3DAbstract Authors: Vidal L, Riekkola ML, Canals A Abstract In recent years, materials science has propelled to the research forefront. Ionic liquids with unique and fascinating properties have also left their footprints to the developments of materials science during the last years. In this review we highlight some of their recent advances and provide an overview at the current status of ionic liquid-modified materials applied in solid-phase extraction, liquid and gas chromatography and capillary electrochromatography with reference to recent applications. In addition, the potential of ionic liquids in the modification of capillary inner wall in capillary electrophoresis is demonstrated. The main target material modified with ionic liquids is silica, but polymers and monoliths have recently ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619256 Mon, 23 Jan 2012 01:13:57 +0100 5619256 http://www.medworm.com/index.php?rid=5619255&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244165%26dopt%3DAbstract Authors: Sato S, Tsueda M, Kanezaki Y, Takenaka S Abstract Hybridization behavior of 24-meric and 105-meric single stranded DNAs derived from CDH4 gene related to cadherin cell-adhesive protein was tested with 24-meric DNA probe in a ferrocenylnaphthalene diimide (FND)-based hybridization assay. Hybridization efficiency in this system was also clarified using chronocoulometric (CC) measurement with Hexaammineruthenium (III) probe (RuHx). This is first example to calculate hybridization efficiency of PCR product with a DNA probe immobilized on the electrode. Although hybridization efficiency was really small for the PCR product as expected (20% for 105-meric PCR product), PCR products carrying aberrant methylation were discriminated from the wild one due to the electrochemical signa... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619255 Mon, 23 Jan 2012 01:13:48 +0100 5619255 http://www.medworm.com/index.php?rid=5619254&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244166%26dopt%3DAbstract Authors: Zhong Z, Li G, Luo Z, Zhu B Abstract A new multi-channel purge and trap system coupled with ion chromatography for the determination of six alkylamines in cosmetics was developed. The proposed method, based on purge and trap of the volatile alkylamines, involved in a miniaturization and multi-channel integration of classical steam distillation and a simple approach for routine labs. The procedure was rapidly achieved within 10min and the matrix interferences could be effectively eliminated. Sample pretreatment frequency was higher than 40h(-1). The linear ranges were 0.1-15mgL(-1) and the detection limits varied from 0.023 to 0.038mgL(-1). This method was successfully utilized to determine the amounts of alkylamines in cosmetics with recoveries ranging from 80.3 to 105.5% ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619254 Mon, 23 Jan 2012 01:13:39 +0100 5619254 http://www.medworm.com/index.php?rid=5619253&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244167%26dopt%3DAbstract Authors: Santos JR, Rangel AO Abstract In this work, the coupling of a commercial monolithic column to a traditional low pressure FIA system is proposed for the analysis of theobromine, theophylline and caffeine in coffee brewed samples using UV detection. The parameters mobile phase composition, flow rate and loop volume were evaluated and discussed considering the various chromatographic parameters in order to enable resolution of the methylxanthines studied within the coffee brewed sample matrix. The analyses of methylxanthines in coffee brewed samples by the proposed methodology were in good agreement with those obtained by the reference procedure based on HPLC. Relative errors were below 6% for all samples analyzed. Detection limits in the selected experimental conditions were... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619253 Mon, 23 Jan 2012 01:13:30 +0100 5619253 http://www.medworm.com/index.php?rid=5619252&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244168%26dopt%3DAbstract Authors: Liu S, Xing J, Zheng Z, Song F, Liu Z, Liu S Abstract Xanthine oxidase (XOD) inhibitors and superoxide anion scavengers play an important role in the treatment of gout and the inhibition of many diseases related to superoxide anion. The respective quantitation of uric acid and superoxide anion by traditional spectroscopic methods is routine in XOD inhibitors and superoxide anion scavengers screening at laboratories worldwide. In the present study, we established an ultrahigh performance liquid chromatography and triple quadrupole mass spectrometry (UHPLC-TQ-MS) method of higher accuracy and speed that combines screening of superoxide anion scavenger and XOD inhibitor in a single analysis by adding WST-1 (2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazoli... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619252 Mon, 23 Jan 2012 01:13:20 +0100 5619252 http://www.medworm.com/index.php?rid=5619251&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244169%26dopt%3DAbstract Authors: Wang Z, Maucher-Fuquay J, Fire SE, Mikulski CM, Haynes B, Doucette GJ, Ramsdell JS Abstract We previously reported a solid-phase extraction (SPE) method for determination of the neurotoxin domoic acid (DA) in both seawater and phytoplankton by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with the purpose of sample desalting without DA pre-concentration. In the present study, we optimized the SPE procedure with seawater and phytoplankton samples directly acidified with aqueous formic acid without addition of organic solvents, which allowed sample desalting and also 20-fold pre-concentration of DA in seawater and phytoplankton samples. In order to reduce MS contamination, a diverter valve was installed between LC and MS to send the LC eluant to waste, except for... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619251 Mon, 23 Jan 2012 01:13:11 +0100 5619251 http://www.medworm.com/index.php?rid=5619250&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244170%26dopt%3DAbstract Authors: Hosseini M, Gupta VK, Ganjali MR, Rafiei-Sarmazdeh Z, Faridbod F, Goldooz H, Badiei AR, Norouzi P Abstract A novel fluorescence nano-chemosensor for Cr(2)O(7)(2-) anion has been developed by assembly of fluorescent aluminum complex of 8-hydroxyquinoline (AlQ(x)) within the channels of modified SBA-15. SBA-SPS-AlQ(x) shows a fluorescence emission at 486nm. The observed remarkable fluorescence of SBA-SPS-AlQ(x) quenches in presence of Cr(2)O(7)(2-) anion. The results showed that this fluorescent nano-material can be a useful chemo-sensor for determination of dichromate anions in aqueous solutions. The linear detecting range of fluorescent nano-chemosensor for Cr(2)O(7)(2-) anion was 0.16-2.9μmolL(-1). The lowest limit of detection (LDL) was also found to be 0.2ngmL(-1) in a... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619250 Mon, 23 Jan 2012 01:13:01 +0100 5619250 http://www.medworm.com/index.php?rid=5619249&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244171%26dopt%3DAbstract Authors: Chai Y, Tian D, Cui H Abstract An electrochemiluminescence (ECL) biosensor for simultaneous detection of adenosine and thrombin in one sample based on bifunctional aptamer and N-(aminobutyl)-N-(ethylisoluminol) functionalized gold nanoparticles (ABEI-AuNPs) was developed. A streptavidin coated gold nanoparticles modified electrode was utilized to immobilize biotinylated bifunctional aptamer (ATA), which consisted of adenosine and thrombin aptamer. The ATA performed as recognition element of capture probe. For adenosine detection, ABEI-AuNPs labeled hybridization probe with a partial complementary sequence of ATA reacted with ATA, leading to a strong ECL response of N-(aminobutyl)-N-(ethylisoluminol) enriched on ABEI-AuNPs. After recognition of adenosine, the hybridization ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619249 Mon, 23 Jan 2012 01:12:51 +0100 5619249 http://www.medworm.com/index.php?rid=5619248&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244172%26dopt%3DAbstract Authors: Civit L, Fragoso A, Hölters S, Dürst M, O'Sullivan CK Abstract An electrochemical genosensor array for the simultaneous detection of three high-risk human papillomavirus (HPV) DNA sequences, HPV16, 18 and 45, exhibiting high sensitivity and selectivity is presented. The electrodes of a 4×4 array were modified via co-immobilization of a 1:100 (mol/mol) mixture of a thiolated probe and an oligoethyleneglycol-terminated bipodal thiol. Detection of synthetic and PCR products was carried out in a sandwich type format, with the target hybridized between a surface immobilized probe and a horseradish peroxidase-labelled secondary reporter probe. The detection limits obtained in the detection of each individual target were in the pM range, allowing the application of this sensor... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619248 Mon, 23 Jan 2012 01:12:41 +0100 5619248 http://www.medworm.com/index.php?rid=5619247&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244173%26dopt%3DAbstract Authors: Lu LM, Zhang XB, Shen GL, Yu RQ Abstract In this paper, for the first time, Cu nanoparticles (CuNPs) were prepared by seed-mediated growth method with Au nanoparticles (AuNPs) playing the role of seeds. Carbon nanotubes (CNTs) and AuNPs were first dropped on the surface of glassy carbon (GC) electrode, and then the electrode was immersed into growth solution that contained CuSO(4) and hydrazine. CuNPs were successfully grown on the surface of the CNTs. The modified electrode showed a very high electrochemical activity for electrocatalytic oxidation of glucose in alkaline medium, which was utilized as the basis of the fabrication of a nonenzymatic biosensor for electrochemical detection of glucose. The biosensor can be applied to the quantification of glucose with a linear ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619247 Mon, 23 Jan 2012 01:12:32 +0100 5619247 http://www.medworm.com/index.php?rid=5619246&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244174%26dopt%3DAbstract Authors: Parra J, Mercader JV, Agulló C, Abad-Somovilla A, Abad-Fuentes A Abstract Azoxystrobin is a modern strobilurin fungicide used around the world to combat prime diseases affecting highly valuable crops. Accordingly, residues of this chemical are frequently found in food, even though mostly under maximum tolerated levels. We herein describe the development of an indirect competitive immunoassay for the determination of azoxystrobin residues. A panel of monoclonal antibodies displaying subnanomolar affinity to azoxystrobin was generated using, as immunizing haptens in mice, four functionalized derivatives carrying the same spacer arm located at different rationally chosen positions. This collection of antibodies was thoroughly characterized with homologous and heterologous an... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619246 Mon, 23 Jan 2012 01:12:22 +0100 5619246 http://www.medworm.com/index.php?rid=5619245&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22244175%26dopt%3DAbstract Authors: Cheng Q, Qu F, Li NB, Luo HQ Abstract In this paper, 1-hexadecyl-3-methylimidazolium bromide (C(16)mimBr)-coated Fe(3)O(4) magnetic nanoparticles (NPs) as an adsorbent of mixed hemimicelles solid-phase extraction was investigated for the preconcentration of two chlorophenols (CPs) in environmental water samples prior to HPLC with UV detection at 285nm. The high surface area and excellent adsorption capacity of the Fe(3)O(4) NPs after modification with C(16)mimBr were utilized adequately in the SPE process. By the rapid isolation of Fe(3)O(4) NPs through placing a strong magnet on the bottom of beaker, the time-consuming preconcentration process of loading large volume sample in conventional SPE method with a column can be avoided. A comprehensive study of the adsorption co... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5619245 Mon, 23 Jan 2012 01:12:12 +0100 5619245 http://www.medworm.com/index.php?rid=5545145&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200301%26dopt%3DAbstract Authors: Andreu-Navarro A, Fernández-Romero JM, Gómez-Hens A Abstract An enzymatic fluorimetric method for the determination of polyphenol compounds in beverages is described, which is based on the temporal inhibition caused by these compounds on the oxidation of the long wavelength fluorophor indocyanine green (λ(ex) 764nm, λ(em) 806nm), in the presence of the enzyme laccase and positively charged gold nanoparticles (AuNPs). The oxidation of the dye gives rise to a fast decrease in its fluorescence, but it is delayed by the polyphenol, obtaining a time period directly proportional to its concentration, which has been used as the analytical parameter. The behaviour of several benzenediols and benzenetriols in the system and the modification of the activity of the enzyme by its ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545145 Wed, 28 Dec 2011 13:14:23 +0100 5545145 http://www.medworm.com/index.php?rid=5545144&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200302%26dopt%3DAbstract Authors: Girard M, Puerta A, Diez-Masa JC, de Frutos M Abstract Human erythropoietin (hEPO), a hormone involved in the formation of red blood cells, is a 30kDa glycoprotein with a high carbohydrate content. The production of recombinant hEPO has made possible its widespread therapeutic use and its banned use in competition sports. Methods to analyze EPO and other erythropoiesis stimulating agents (ESAs) are necessary for the characterization and quality control of these biopharmaceuticals and also for doping control. In this paper, high resolution separation methods, namely high performance liquid chromatography (HPLC) and capillary electrophoresis (CE), with special attention to CE-coupled mass spectrometry, are reviewed. The usefulness of these techniques when applied in differen... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545144 Wed, 28 Dec 2011 13:14:08 +0100 5545144 http://www.medworm.com/index.php?rid=5545143&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200303%26dopt%3DAbstract Authors: Takasaki Y, Sakagawa S, Inagaki K, Fujii S, Sabarudin A, Umemura T, Haraguchi H Abstract Accurate quantification of DNA is highly important in various fields. Determination of phosphorus by ICP-MS is one of the most effective methods for accurate quantification of DNA due to the fixed stoichiometry of phosphate to this molecule. In this paper, a smart and reliable method for accurate quantification of DNA fragments and oligodeoxythymidilic acids by hyphenated HPLC/ICP-MS equipped with a highly efficient interface device is presented. The interface was constructed of a home-made capillary-attached micronebulizer and temperature-controllable cyclonic spray chamber (IsoMist). As a separation column for DNA samples, home-made methacrylate-based weak anion-exchange monolith was... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545143 Wed, 28 Dec 2011 13:13:52 +0100 5545143 http://www.medworm.com/index.php?rid=5545142&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200304%26dopt%3DAbstract Authors: Chen C, Li SX, Wang SM, Liang SW Abstract Herbal medicine has been successfully applied in clinical therapeutics throughout the world. In this paper, various information contents in addition to a best-first search strategy are proposed for improving prediction quality of quantitative profile-efficacy relationship (QPER). As a demonstration, a QPER model was constructed to predict the blood-clotting time increasing effect of Naodesheng prescription, a widely used herbal medicine in China. Evaluated by both the self-consistency test and the rigorous jackknife test, the predictive accuracy was increased by feeding the model with the merged information contents compared to only with the common chromatographic peak areas. The confirmation experiment exhibited that the predicted... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545142 Wed, 28 Dec 2011 13:13:33 +0100 5545142 http://www.medworm.com/index.php?rid=5545141&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200305%26dopt%3DAbstract Authors: Gholivand MB, Torkashvand M, Malekzadeh G Abstract A computational approach was used for screening functional monomers and polymerization solvent in the rational design of molecularly imprinted polymers (MIPs). It was based on the comparison of the binding energy of the complexes between the template and functional monomers. On the basis of computational results, acrylamide (AAM) and toluene were selected as functional monomer and polymerization solvent, respectively. The MIP, embedded in the carbon paste electrode, functioned as a selective recognition element and pre-concentrator agent for cyanazine determination by using cathodic stripping voltammetric method. The MIP-CP electrode showed very high recognition ability in comparison with NIP-CPE. Some parameters affecting... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545141 Wed, 28 Dec 2011 13:13:14 +0100 5545141 http://www.medworm.com/index.php?rid=5545140&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200306%26dopt%3DAbstract In this study, we firstly demonstrated that Bst DNA polymerase shows specific recognition and function on the T-Hg(2+)-T biomimetic structure. Based on this, a novel available electrochemiluminescence (ECL) sensor for Hg(2+) has been developed. In this strategy, magnet beads tagged primer was designed to complementary to the region of the circular padlock probe but with two T-T mismatches at the 3' end. The mismatched primers cannot be extended by Bst DNA polymerase in the absence of Hg(2+). Stable T-Hg(2+)-T can be formed in the presence of Hg(2+), thus induces the elongation and amplification reaction by DNA polymerase with a rolling circular amplification (RCA) mechanism. Subsequently, the resulted RCA products are hybridized with the tris (bipyridine) ruthenium (TBR)-tagged probes and ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545140 Wed, 28 Dec 2011 13:12:55 +0100 5545140 http://www.medworm.com/index.php?rid=5545139&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200307%26dopt%3DAbstract Authors: Nian H, Wang J, Wu H, Lo JG, Chiu KH, Pounds JG, Lin Y Abstract A disposable sensor for the determination of cotinine in human serum was developed based on immunochromatographic test strip and quantum dot label. In this assay, cotinine linked with quantum dot competes with cotinine in sample to bind to anti-cotinine antibody in the test strip and the quantum dots serve as signal vehicles for electrochemical readout. Some parameters governing the performance of the sensor were optimized. The sensor shows a wide linear range from 1ngmL(-1) to 100ngmL(-1) cotinine with a detection limit of 1.0ngmL(-1). The sensor was validated with spiked human serum samples and it was found that this method was reliable in measuring cotinine in human serum. The results demonstrate that this ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545139 Wed, 28 Dec 2011 13:12:34 +0100 5545139 http://www.medworm.com/index.php?rid=5545138&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200308%26dopt%3DAbstract Authors: Berton P, Martinis EM, Martinez LD, Wuilloud RG Abstract In the present work, a simple and rapid analytical method based on application of ionic liquids (ILs) for inorganic Co(II) species (iCo) microextraction in a variety of nutrient supplements was developed. Inorganic Co was initially chelated with 1-nitroso-2-naphtol (1N2N) reagent followed by a modern technique named ultrasound-assisted temperature-controlled ionic liquid dispersive liquid phase microextraction (USA-TILDLME). The extraction was performed with 1-hexyl-3-methylimidazolium hexafluorophosphate [C(6)mim][PF(6)] with the aid of ultrasound to improve iCo recovery. Finally, the iCo-enriched IL phase was solubilized in methanol and directly injected into an electrothermal atomic absorption spectrometer (ETAAS)... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545138 Wed, 28 Dec 2011 13:12:10 +0100 5545138 http://www.medworm.com/index.php?rid=5545137&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200309%26dopt%3DAbstract Authors: Bagheri H, Aghakhani A Abstract A headspace adsorptive microextraction technique was developed using a novel polyaniline-nylon-6 (PANI-N6) nanofiber sheet, fabricated by electrospinning. The homogeneity and the porosity of the prepared PANI-N6 sheet were studied using the scanning electron microscopy (SEM) and nanofibers diameters were found to be around 200nm. The novel nanofiber sheet was examined as an extracting medium to isolate some selected chlorobenzenes (CBs), as model compounds, from aquatic media. The extracted analytes were desorbed using μL-amounts of solvent and eventually an aliquot of extractant was injected into gas chromatography-mass spectrometry (GC-MS). Various parameters affecting the extraction and desorption processes were optimized. The developed ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545137 Wed, 28 Dec 2011 13:11:47 +0100 5545137 http://www.medworm.com/index.php?rid=5545136&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200310%26dopt%3DAbstract Authors: Farajzadeh MA, Djozan D, Khorram P Abstract In the present work a new, simple, rapid and environmentally friendly dispersive liquid-liquid microextraction (DLLME) method has been developed for extraction/preconcentration of some triazole pesticides in aqueous samples and in grape juice. The extract was analyzed with gas chromatography-flame ionization detection (GC-FID) or gas chromatography-mass spectrometry (GC-MS). The DLLME method was performed in a narrow-bore tube containing aqueous sample. Acetonitrile and a mixture of n-hexanol and n-hexane (75:25, v/v) were used as disperser and extraction solvents, respectively. The effect of several factors that influence performance of the method, including the chemical nature and volume of the disperser and extraction solvents... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545136 Wed, 28 Dec 2011 13:11:26 +0100 5545136 http://www.medworm.com/index.php?rid=5545135&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200311%26dopt%3DAbstract Authors: Hyder M, Genberg J, Jönsson JÅ Abstract A method based on hollow fiber liquid phase microextraction (HF-LPME) for analysis of pinic acid and pinonic acid was developed and for the first time successfully applied to ambient aerosol samples. In this method, the aerosol samples were dissolved in 0.05M H(2)SO(4) and the solution was extracted using three-phase HF-LPME where donor phase was 0.1M (NH(4))(2)CO(3). Different parameters like type of organic solvent for membrane phase, extraction time and stirring speed etc. were optimized. Optimum extraction time was 4.5h and optimum-stirring speed was found to be 900rpm. We used 6-undecanone as organic phase along with tri-n-octylphosphine oxide (optimum TOPO contents was 15% w/v), which gave an enormous enrichment for both pini... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545135 Wed, 28 Dec 2011 13:11:06 +0100 5545135 http://www.medworm.com/index.php?rid=5545134&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200312%26dopt%3DAbstract Authors: Khosravi K, Hoque ME, Dimock B, Hintelmann H, Metcalfe CD Abstract Titanium dioxide (i.e. TiO(2)) in nano-form is a constituent of many nanomaterials that are used in sunscreens, cosmetics, industrial products and in biomedical applications. Quantification of TiO(2) nanoparticles in various matrixes is a topic of great interest for researchers studying the potential health and environmental impacts of nanoparticles. However, analysis of TiO(2) as Ti(4+) is difficult because current digestion techniques require use of strong acids that may be a health and safety risk in the laboratory. To overcome this problem, we developed a new method to digest TiO(2) nanoparticles using ammonium persulfate as a fusing reagent. The digestion technique requires short times to completion an... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545134 Wed, 28 Dec 2011 13:10:46 +0100 5545134 http://www.medworm.com/index.php?rid=5545133&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200313%26dopt%3DAbstract Authors: Wang Y, Luo X, Tang J, Hu X, Xu Q, Yang C Abstract A new approach to performing extraction and preconcentration employing functionalized magnetic nanoparticles for the determination of trace metals is presented. Alumina-coated iron oxide nanoparticles were synthesized and used as the solid support. The nanoparticles were functionalized with sodium dodecyl sulfate and used as adsorbents for solid phase extraction of the analyte. Extraction, elution, and detection procedures were performed sequentially in the sequential injection lab-on-valve (SI-LOV) system followed by electrothermal atomic absorption spectrometry (ETAAS). Mixtures of hydrophobic analytes were successfully extracted from solution using the synthesized magnetic adsorbents. The potential use of the establishe... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545133 Wed, 28 Dec 2011 13:10:12 +0100 5545133 http://www.medworm.com/index.php?rid=5545132&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200314%26dopt%3DAbstract Authors: Fedyunina NN, Seregina IF, Bolshov MA, Okina OI, Lyapunov SM Abstract Different methods of rock sample digestion for final analysis by ICP-MS technique are investigated. It is shown that only basic rocks can be quantitatively digested in a microwave (MW) field with the mixture of HF and HNO(3) acids at 210°C for 60min. The addition of HCl and H(3)BO(3) provides complete digestion of andesites and some types of granites. Even at maximal temperature in the used MW oven of 210°C syenites, granodiorites and albitized granites are not digested. These types of rocks are not digested in a closed Teflon autoclave for 16h and can be digested only by fusion with lithium metaborate. The reason for such behavior is discussed. To avoid problems with the introduction of heavily acidic... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545132 Wed, 28 Dec 2011 13:09:47 +0100 5545132 http://www.medworm.com/index.php?rid=5545131&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200315%26dopt%3DAbstract Authors: Schug KA, Wang E, Shen S, Rao S, Smith SM, Hunt L, Mydlarz LD Abstract A direct affinity screening - mass spectrometry assay, coupled to liquid chromatography, is presented as a tool for natural product drug discovery. Using the assay, fractionated extracts from a Caribbean gorgonian coral were shown to contain a new chemical entity (NCE) which binds to a mimic of the Gram positive bacterial cell wall (lysine-d-alanine-d-alanine). Conditions for observation of a specific noncovalent complex between the NCE and the target mimic using electrospray ionization-mass spectrometry were validated in a series of positive and negative control experiments, which featured flow injection analysis-based titrations. While the structural identity of the NCE could not be determined due to ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545131 Wed, 28 Dec 2011 13:09:17 +0100 5545131 http://www.medworm.com/index.php?rid=5545130&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200316%26dopt%3DAbstract Authors: Chen J, Chen H, Zhou C, Xu J, Yuan F, Wang L Abstract Based on NaYF(4):Yb(3+), Er(3+) upconversion nanocrystals as donor and 4-((4-(2-aminoethylamino)naphthalen-1-yl)diazenyl) benzenesulfonic acid dihydrochloride (ANDBS) as acceptor, an efficient luminescence energy transfer (LET) system was developed for selective and sensitive determination of trace amounts of nitrite. Based on Griess Reaction, ANDBS was generated by the quantitative reaction of nitrite, sulfanilamide and N-(1-naphtyl)-ethylenediamine dihydrochloride (N1NED). The degree of the overlaps between the emission spectrum of NaYF(4):Yb(3+), Er(3+) and the absorption spectrum of ANDBS were effective for luminescence energy transfer. Under the optimal condition, the upconversion luminescence quenching of NaYF(4):... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545130 Wed, 28 Dec 2011 13:08:36 +0100 5545130 http://www.medworm.com/index.php?rid=5545129&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200317%26dopt%3DAbstract Authors: Gáspár S, David S, Polonschii C, Marcu I, Gheorghiu M, Gheorghiu E Abstract The complexity of the cellular response, induced even by the simplest experimental stimulus, requires an increased number of cellular parameters to be simultaneously monitored. An all electrochemical system allowing the simultaneous and real-time monitoring of both cell adherence and superoxide release into the extracellular space was developed to address this challenge. Cell adherence (to neighboring cells and to substrate) was monitored using non-faradaic impedance spectroscopy while the superoxide release was monitored using a cytochrome c-based amperometric biosensor. The system was used to observe for the first time how these two cellular parameters are changing in real-time for renal cells ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545129 Wed, 28 Dec 2011 13:08:10 +0100 5545129 http://www.medworm.com/index.php?rid=5545128&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200318%26dopt%3DAbstract In this study, a comprehensive 2D chromatography approach was developed for the separation and identification of membrane permeable compounds in a famous traditional Chinese medicine of Schisandra chinensis. The first dimensional column was the immobilized liposome chromatography (ILC) column, which mimics the biological membranes and can be used to study drug-membrane interactions in liquid chromatography. Using an automatic ten-port switching valve equipped with two sample loops, the section of the first-dimension was introduced in the second-dimension consist of a silica monolithic column. More than 40 components in Schisandra chinensis were resolved by using the developed separation system and among them 14 compounds were identified interacting with the ILC column based on their retent... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545128 Wed, 28 Dec 2011 13:07:43 +0100 5545128 http://www.medworm.com/index.php?rid=5545127&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200319%26dopt%3DAbstract Authors: Han SY, Liang C, Qiao JQ, Lian HZ, Ge X, Chen HY Abstract The retention factor corresponding to pure water in reversed-phase high performance liquid chromatography (RP-HPLC), k(w), was commonly obtained by extrapolation of retention factor (k) in a mixture of organic modifier and water as mobile phase in tedious experiments. In this paper, a relationship between logk(w) and logk for directly determining k(w) has been proposed for the first time. With a satisfactory validation, the approach was confirmed to enable easy and accurate evaluation of k(w) for compounds in question with similar structure to model compounds. Eight PCB congeners with different degree of chlorination were selected as a training set for modeling the logk(w)-logk correlation on both silica-based C(8) ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545127 Wed, 28 Dec 2011 13:07:19 +0100 5545127 http://www.medworm.com/index.php?rid=5545126&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200320%26dopt%3DAbstract Authors: Li R, He Q, Hu Z, Zhang S, Zhang L, Chang X Abstract The originality on the high efficiency of murexide modified halloysite nanotubes as a new adsorbent of solid phase extraction has been reported to preconcentrate and separate Pd(II) in solution samples. The new adsorbent was confirmed by Fourier transformed infrared spectra, X-ray diffraction, scanning electron microscope, transmission electron microscope and N(2) adsorption-desorption isotherms. Effective preconcentration conditions of analyte were examined using column procedures prior to detection by inductively coupled plasma-optical emission spectrometry (ICP-OES). The effects of pH, the amount of adsorbent, the sample flow rate and volume, the elution condition and the interfering ions were optimized in detail. Und... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5545126 Wed, 28 Dec 2011 13:06:50 +0100 5545126 http://www.medworm.com/index.php?rid=5527216&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fsites%2Fentrez%3Fcmd%3DSearch%26db%3Dpubmed%26term%3D%28%28%28%2522Anal%2520Chim%2520Acta%2522%29%2520AND%2520%25222011%252F11%252F17%252009.36%2522%255BMHDA%255D%253A%25222011%252F12%252F22%252009.18%2522%255BMHDA%255D%29%29%2520NOT%2520%28%28%2520%28%28%2522Anal%2520Chim%2520Acta%2522%255BTIAB%255D%29%29%2520AND%2520%25220001%2522%255BEDAT%255D%253A%25222011%252F11%252F17%252009.36%2522%255BEDAT%255D%29%29 146 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: "Anal Chim Acta" These pubmed results were generated on 2011/12/22PubMed, a service of the National Library of Medicine, includes over 15 million citations for biomedical articles back to the 1950's. These citations are from MEDLINE and additional life science journals. PubMed includes links to many sites providing full text articles and other related resources. (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5527216 Thu, 22 Dec 2011 14:18:02 +0100 5527216 http://www.medworm.com/index.php?rid=5377398&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fsites%2Fentrez%3Fcmd%3DSearch%26db%3Dpubmed%26term%3D%28%28%28%2522Anal%2520Chim%2520Acta%2522%29%2520AND%2520%25222011%252F10%252F07%252023.39%2522%255BMHDA%255D%253A%25222011%252F11%252F05%252008.15%2522%255BMHDA%255D%29%29%2520NOT%2520%28%28%2520%28%28%2522Anal%2520Chim%2520Acta%2522%255BTIAB%255D%29%29%2520AND%2520%25220001%2522%255BEDAT%255D%253A%25222011%252F10%252F07%252023.39%2522%255BEDAT%255D%29%29 121 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: "Anal Chim Acta" These pubmed results were generated on 2011/11/05PubMed, a service of the National Library of Medicine, includes over 15 million citations for biomedical articles back to the 1950's. These citations are from MEDLINE and additional life science journals. PubMed includes links to many sites providing full text articles and other related resources. (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5377398 Sat, 05 Nov 2011 12:15:02 +0100 5377398 http://www.medworm.com/index.php?rid=5294364&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962340%26dopt%3DAbstract Authors: Buydens L, Van Espen P, Rutan S PMID: 21962340 [PubMed - in process] (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294364 Sat, 08 Oct 2011 03:46:26 +0100 5294364 http://www.medworm.com/index.php?rid=5294363&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962341%26dopt%3DAbstract Authors: Filzmoser P, Todorov V Abstract General ideas of robust statistics, and specifically robust statistical methods for calibration and dimension reduction are discussed. The emphasis is on analyzing high-dimensional data. The discussed methods are applied using the packages chemometrics and rrcov of the statistical software environment R. It is demonstrated how the functions can be applied to real high-dimensional data from chemometrics, and how the results can be interpreted. PMID: 21962341 [PubMed - in process] (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294363 Sat, 08 Oct 2011 03:46:15 +0100 5294363 http://www.medworm.com/index.php?rid=5294362&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962342%26dopt%3DAbstract We present a strategy based on the stability of putative biomarkers under perturbation of the data, and show that in several cases important gains can be achieved. The strategy is very general and can be applied with all common biomarker identification methods; it also has the advantage that it does not rely on error estimates from crossvalidation, that in this setting tend to be highly variable. PMID: 21962342 [PubMed - in process] (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294362 Sat, 08 Oct 2011 03:46:04 +0100 5294362 http://www.medworm.com/index.php?rid=5294361&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962343%26dopt%3DAbstract Authors: Rübensam G, Barreto F, Hoff RB, Kist TL, Pizzolato TM Abstract In this work a method is proposed and demonstrated for the analysis of the macrocyclic lactones abamectin, doramectin, eprinomectin, ivermectin and moxidectin in bovine milk by liquid chromatography coupled to mass spectrometry (LC-MS/MS) and liquid chromatography with fluorescence detection (LC-FL). The method is based on liquid-liquid extraction followed by a low temperature purification (LLE-LTP) step. Moreover, the proposed method was validated according to the Commission Decision 2002/657/EC, using LC-MS/MS and LC-FL for confirmatory and quantitative analysis, respectively. For LC-MS/MS the recovery rates observed ranged from 101.2 to 141.6% with coefficient of variation from 2.6 to 19.8%. For LC-FL the r... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294361 Sat, 08 Oct 2011 03:45:54 +0100 5294361 http://www.medworm.com/index.php?rid=5294360&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962344%26dopt%3DAbstract Authors: Pierna JA, Lecler B, Conzen JP, Niemoeller A, Baeten V, Dardenne P Abstract In the present study, different multivariate regression techniques have been applied to two large near-infrared data sets of feed and feed ingredients in order to fulfil the regulations and laws that exist about the chemical composition of these products. The aim of this paper was to compare the performances of different linear and nonlinear multivariate calibration techniques: PLS, ANN and LS-SVM. The results obtained show that ANN and LS-SVM are very powerful methods for non-linearity but LS-SVM can also perform quite well in the case of linear models. Using LS-SVM an improvement of the RMS for independent test sets of 10% is obtained in average compared to ANN and of 24% compared to PLS. PMI... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294360 Sat, 08 Oct 2011 03:45:44 +0100 5294360 http://www.medworm.com/index.php?rid=5294359&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962345%26dopt%3DAbstract Authors: Rocha WF, Poppi RJ Abstract Raman spectroscopy and control charts based on the net analyte signal (NAS) were applied to polymorphic characterization of carbamazepine. Carbamazepine presents four polymorphic forms: I-IV (dihydrate). X-ray powder diffraction was used as a reference technique. The control charts were built generating three charts: the NAS chart that corresponds to the analyte of interest (form III in this case), the interference chart that corresponds to the contribution of other compounds in the sample and the residual chart that corresponds to nonsystematic variations. For each chart, statistical limits were developed using samples within the quality specifications. It was possible to identify the different polymorphic forms of carbamazepine present in phar... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294359 Sat, 08 Oct 2011 03:45:34 +0100 5294359 http://www.medworm.com/index.php?rid=5294358&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962346%26dopt%3DAbstract Authors: Doeswijk TG, Smilde AK, Hageman JA, Westerhuis JA, van Eeuwijk FA Abstract The combination of the different data sources for classification purposes, also called data fusion, can be done at different levels: low-level, i.e. concatenating data matrices, medium-level, i.e. concatenating data matrices after feature selection and high-level, i.e. combining model outputs. In this paper the predictive performance of high-level data fusion is investigated. Partial least squares is used on each of the data sets and dummy variables representing the classes are used as response variables. Based on the estimated responses yˆ(j) for data set j and class k, a Gaussian distribution p(g(k)|yˆ(j)) is fitted. A simulation study is performed that shows the theoretical performance of high-... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294358 Sat, 08 Oct 2011 03:45:24 +0100 5294358 http://www.medworm.com/index.php?rid=5294357&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962347%26dopt%3DAbstract Authors: Varmuza K, Engrand C, Filzmoser P, Hilchenbach M, Kissel J, Krüger H, Silén J, Trieloff M Abstract Random projection (RP) is a simple and fast linear method for dimensionality reduction of high-dimensional multivariate data, independent from the data. The method is briefly described and a new memory-saving algorithm is presented for the generation of random projection vectors. Application of RP to data from scanning experiments with a time-of-flight secondary ion mass spectrometer (TOF-SIMS) showed that data reduced by RP have a satisfying discriminant property for separating target material and minerals without using any knowledge about the composition of the sample. A selection method - based on low dimensional RP data - is described and successfully tested for automat... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294357 Sat, 08 Oct 2011 03:45:13 +0100 5294357 http://www.medworm.com/index.php?rid=5294356&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962348%26dopt%3DAbstract Authors: Acharjee A, Kloosterman B, de Vos RC, Werij JS, Bachem CW, Visser RG, Maliepaard C Abstract In the post-genomic era, high-throughput technologies have led to data collection in fields like transcriptomics, metabolomics and proteomics and, as a result, large amounts of data have become available. However, the integration of these ∼omics data sets in relation to phenotypic traits is still problematic in order to advance crop breeding. We have obtained population-wide gene expression and metabolite (LC-MS) data from tubers of a diploid potato population and present a novel approach to study the various ∼omics datasets to allow the construction of networks integrating gene expression, metabolites and phenotypic traits. We used Random Forest regression to select subsets of ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294356 Sat, 08 Oct 2011 03:45:03 +0100 5294356 http://www.medworm.com/index.php?rid=5294355&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962349%26dopt%3DAbstract Authors: Devos O, Mouton N, Sliwa M, Ruckebusch C Abstract In femtosecond transient absorption spectroscopy, artifact contributions are usually observed at ultra-short time scale. These complex signals are very challenging because of their nature, related to ultrafast phenomena, and because they strongly distort the structure of the spectrokinetic data. The purpose of this work is to evaluate the potential of baseline correction methods for femtosecond transient absorption spectroscopy data pre-processing. Indeed, artifacts removal should ideally be performed before multivariate data analysis. The work is thus mainly focused on two different approaches which are filtering by discrete wavelet transform, on the one hand, and smoothing by asymmetric least squares, on the other hand. T... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294355 Sat, 08 Oct 2011 03:44:52 +0100 5294355 http://www.medworm.com/index.php?rid=5294354&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962350%26dopt%3DAbstract In this study we have evaluated to what extent a non-linear model, kernel-based orthogonal projections to latent structures (K-OPLS), can provide enhanced predictive performance compared to the linear OPLS model. Just like its linear counterpart, K-OPLS provides separate model components for predictive variation and response-orthogonal structured noise. The improved model interpretation by this separate modeling is a property unique to K-OPLS in comparison to other kernel-based models. Simulated annealing (SA) was used for effective and automated optimization of the kernel-function parameter in K-OPLS (SA-K-OPLS). Our results reveal that the non-linear K-OPLS model provides improved prediction performance in three separate metabonomic data sets compared to the linear OPLS model. We also de... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294354 Sat, 08 Oct 2011 03:44:42 +0100 5294354 http://www.medworm.com/index.php?rid=5294353&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962351%26dopt%3DAbstract Authors: Thygesen J, van den Berg F Abstract The main part of the wide array of different calibration transfer methods found in literature is dedicated to two-way data arrangements (m×n matrices). Less work has been done within the area of calibration transfer for three-way data structures (m×n×l tensors) such as calibrations made for excitation-emission-matrix (EEM) fluorescence spectra. There are two possible ways to attack the problem for EEM transfer. Either the tensors are unfolded to two-way data, whereby the existing methods can be applied, or new methods dedicated to three-way calibration transfer have to be developed. This paper presents and compares both. It was possible to make a local linear pixel-based model that could be used for transfer of EEM's. This new method ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294353 Sat, 08 Oct 2011 03:44:32 +0100 5294353 http://www.medworm.com/index.php?rid=5294352&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962352%26dopt%3DAbstract The objective of this study was to investigate the potential of mid-infrared (mid-IR) spectroscopy to measure the milk composition using two different measurement modes: micro attenuated total reflection (μATR) and high throughput transmission (HTT). Partial least squares (PLS) regression was used for prediction of fat, crude protein, lactose and urea after preprocessing IR data and selecting the most informative wavenumber variables. The prediction accuracies were determined separately for raw and homogenized copies of a wide range of milk samples in order to estimate the possibility for on-line analysis of the milk. In case of fat content both measurement modes resulted in an excellent prediction for homogenized samples (R(2)>0.92) but in poor results for raw samples (R(2)<0.70). ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294352 Sat, 08 Oct 2011 03:44:22 +0100 5294352 http://www.medworm.com/index.php?rid=5294351&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962353%26dopt%3DAbstract Authors: Dejaegher B, Dhooghe L, Goodarzi M, Apers S, Pieters L, Vander Heyden Y Abstract This paper describes the construction of a QSAR model to relate the structures of various derivatives of neocryptolepine to their anti-malarial activities. QSAR classification models were build using Linear Discriminant Analysis (LDA), Quadratic Discriminant Analysis (QDA), Classification and Regression Trees (CART), Partial Least Squares - Discriminant Analysis (PLS-DA), Orthogonal Projections to Latent Structures - Discriminant Analysis (OPLS-DA), and Support Vector Machines for Classification (SVM-C), using four sets of molecular descriptors as explanatory variables. Prior to classification, the molecules were divided into a training and a test set using the duplex algorithm. The different ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294351 Sat, 08 Oct 2011 03:44:12 +0100 5294351 http://www.medworm.com/index.php?rid=5294350&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962354%26dopt%3DAbstract In this study, a fingerprint methodology for PCR based on high-performance liquid chromatography (HPLC) was developed and validated. A total of 69 fingerprints of authenticated PCR samples, commercial PCR samples, mixed peel samples, and other Citrus peels were recorded. Exploratory data analysis allowed optimizing the extraction procedure and detecting mixed peel samples. Once the optimizations were performed and the method validated, discrimination between the authentic PCR samples and all other samples was performed by p-Discriminant Partial Least Squares. The established model was able to differentiate between classes with a high reliability for each sample. Furthermore, evaluation of the score and loading plots of the model indicated nobiletin, tangeretin, naringin and hesperidin as i... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294350 Sat, 08 Oct 2011 03:44:02 +0100 5294350 http://www.medworm.com/index.php?rid=5294349&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962355%26dopt%3DAbstract Authors: Postma GJ, Krooshof PW, Buydens LM Abstract Kernel partial least squares (KPLS) and support vector regression (SVR) have become popular techniques for regression of complex non-linear data sets. The modeling is performed by mapping the data in a higher dimensional feature space through the kernel transformation. The disadvantage of such a transformation is, however, that information about the contribution of the original variables in the regression is lost. In this paper we introduce a method which can retrieve and visualize the contribution of the variables to the regression model and the way the variables contribute to the regression of complex data sets. The method is based on the visualization of trajectories using so-called pseudo samples representing the original var... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294349 Sat, 08 Oct 2011 03:43:51 +0100 5294349 http://www.medworm.com/index.php?rid=5294348&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962356%26dopt%3DAbstract Authors: Al-Mbaideen A, Benaissa M Abstract In this paper a new model based on frequency self deconvolution (FSD) is proposed for the quantitative analysis of a near infrared (NIR) spectrum. The model couples FSD and partial least square regression (PLS). The grid search optimization method is used to select the optimal values of the full width at half height (FWHH) and the truncation point of the apodization function. The proposed FSD-PLS provides a significant improvement in the prediction ability of the PLS model. Furthermore, a modification of the new FSD-PLS method is introduced to enable the removal of the baseline variations from the NIR spectra. The proposed models were validated using absorbance spectra of mixtures composed from glucose, urea and triacetin in a phosphate b... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294348 Sat, 08 Oct 2011 03:43:41 +0100 5294348 http://www.medworm.com/index.php?rid=5294347&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962357%26dopt%3DAbstract Authors: Fjodorova N, Novič M, Diankova T Abstract Process optimization involves the minimization (or maximization) of an objective function, that can be established from a technical and (or) economic viewpoint taking into account safety of process. The basic idea of the optimization method using neural network (NN) is to replace the model equations (which traditionally obtained using, for example, the surface response design or others methods) by an equivalent NN. The feed-forward bottleneck neural network (FFBN) as a mapping technique is described and evaluated. From the 2D maps the optimal parameters of pigment dyeing of high performance fibers on the bases of poly-amide benzimidazole (PABI) and polyimide (arimid) are discussed. The studied fibers were treated in 32 experiments... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294347 Sat, 08 Oct 2011 03:43:30 +0100 5294347 http://www.medworm.com/index.php?rid=5294346&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962358%26dopt%3DAbstract Authors: Engelen S, Hubert M Abstract To explore multi-way data, different methods have been proposed. Here, we study the popular PARAFAC (Parallel factor analysis) model, which expresses multi-way data in a more compact way, without ignoring the underlying complex structure. To estimate the score and loading matrices, an alternating least squares procedure is typically used. It is however well known that least squares techniques suffer from outlying observations, making the models useless when outliers are present in the data. In this paper, we present a robust PARAFAC method. Essentially, it searches for an outlier-free subset of the data, on which we can then perform the classical PARAFAC algorithm. An outlier map is constructed to identify outliers. Simulations and examples sho... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294346 Sat, 08 Oct 2011 03:43:20 +0100 5294346 http://www.medworm.com/index.php?rid=5294345&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962359%26dopt%3DAbstract Authors: Goodarzi M, Freitas MP, Heyden YV Abstract For a series of thiocarbamates, non-nucleoside HIV-1 reverse transcriptase inhibitors, few descriptors have been selected from a large pool of theoretical molecular descriptors by means of the ant colony optimization (ACO) feature selection method. The selected descriptors were correlated with the bioactivities of the molecules using the well known multiple linear regression (MLR) and partial least squares (PLS) regression techniques, and, to account for nonlinearity, also PLS coupled to radial basis function (RBF) on the one hand and radial basis function neural network (RBFNN) on the other. In this case study, the RBF/PLS results were better than those from the other modeling techniques applied. The prediction ability of the ACO... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294345 Sat, 08 Oct 2011 03:43:10 +0100 5294345 http://www.medworm.com/index.php?rid=5294344&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962360%26dopt%3DAbstract Authors: Villar A, Gorritxategi E, Otaduy D, Ciria JI, Fernandez LA Abstract This paper describes the calibration process of a Visible-Near Infrared sensor for the condition monitoring of a gas engine's lubricating oil correlating transmittance oil spectra with the degradation of a gas engine's oil via a regression model. Chemometric techniques were applied to determine different parameters: Base Number (BN), Acid Number (AN), insolubles in pentane and viscosity at 40°C. A Visible-Near Infrared (400-1100nm) sensor developed in Tekniker research center was used to obtain the spectra of artificial and real gas engine oils. In order to improve sensor's data, different preprocessing methods such as smoothing by Saviztky-Golay, moving average with Multivariate Scatter Correction or Sta... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294344 Sat, 08 Oct 2011 03:43:00 +0100 5294344 http://www.medworm.com/index.php?rid=5294343&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962361%26dopt%3DAbstract Authors: Piqueras S, Duponchel L, Tauler R, de Juan A Abstract MCR-ALS is a resolution method that has been applied in many different fields, such as process analysis, environmental data and, recently, hyperspectral image analysis. In this context, the algorithm provides the distribution maps and the pure spectra of the image constituents from the sole information in the raw image measurement. Based on the distribution maps and spectra obtained, additional information can be easily derived, such as identification of constituents when libraries are available or quantitation within the image, expressed as constituent signal contribution. This work summarizes first the protocol followed for the resolution on two examples of kidney calculi, taken as representations of images with major... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294343 Sat, 08 Oct 2011 03:42:50 +0100 5294343 http://www.medworm.com/index.php?rid=5294342&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962362%26dopt%3DAbstract In this study, a Bayesian approach is proposed to address this concern. Results reliability is defined here as "the probability (π) of an analytical method to provide analytical results (X) within predefined acceptance limits (±λ) around their reference or conventional true concentration values (μ(T)) over a defined concentration range and under given environmental and operating conditions." By providing the minimum reliability probability (π(min)) needed for the subsequent routine application of the method, as well as specifications or acceptance limits (±λ), the proposed Bayesian approach provides the effective probability of obtaining reliable future analytical results over the whole concentration range investigated. This is summarised in a single graph: the reliability profile. ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294342 Sat, 08 Oct 2011 03:42:39 +0100 5294342 http://www.medworm.com/index.php?rid=5294341&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962363%26dopt%3DAbstract Authors: Ramos D, Zadora G Abstract In this work, a selection of the best features for multivariate forensic glass classification using Scanning Electron Microscopy coupled with an Energy Dispersive X-ray spectrometer (SEM-EDX) has been performed. This has been motivated by the fact that the databases available for forensic glass classification are sparse nowadays, and the acquisition of SEM-EDX data is both costly and time-consuming for forensic laboratories. The database used for this work consists of 278 glass objects for which 7 variables, based on their elemental compositions obtained with SEM-EDX, are available. Two categories are considered for the classification task, namely containers and car/building windows, both of them typical in forensic casework. A multivariate model... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294341 Sat, 08 Oct 2011 03:42:29 +0100 5294341 http://www.medworm.com/index.php?rid=5294340&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962364%26dopt%3DAbstract Authors: de Rooi J, Eilers P Abstract The output of many instruments can be modeled as a convolution of an impulse response and a series of sharp spikes. Deconvolution considers the inverse problem: estimate the input spike train from an observed (noisy) output signal. We approach this task as a linear inverse problem, solved using penalized regression. We propose the use of an L(0) penalty and compare it with the more common L(2) and L(1) penalties. In all cases a simple and iterative weighted regression procedure can be used. The model is extended with a smooth component to handle drifting baselines. Application to three different data sets shows excellent results. PMID: 21962364 [PubMed - in process] (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294340 Sat, 08 Oct 2011 03:42:19 +0100 5294340 http://www.medworm.com/index.php?rid=5294339&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962365%26dopt%3DAbstract In this study, chemometric predictive models were developed from near infrared (NIR) spectra for the quantitative determination of saturates, aromatics, resins and asphaltens (SARA) in heavy petroleum products. Model optimisation was based on adequate pre-processing and/or variable selection. In addition to classical methods, the potential of a genetic algorithm (GA) optimisation, which allows the co-optimisation of pre-processing methods and variable selection, was evaluated. The prediction results obtained with the different models were compared and decision regarding their statistical significance was taken applying a randomization t-test. Finally, the results obtained for the root mean square errors of prediction (and the corresponding concentration range) expressed in %(w/w), are 1.51... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294339 Sat, 08 Oct 2011 03:42:09 +0100 5294339 http://www.medworm.com/index.php?rid=5294338&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962366%26dopt%3DAbstract Authors: Mesquita DP, Amaral AL, Ferreira EC Abstract This work focuses on the use of chemometric techniques for identifying activated sludge process abnormalities. Chemometric methods combined with image analysis can improve activated sludge systems monitoring and minimize the need of analytical measurements. For that purpose data was collected from aggregated and filamentous biomass, biomass composition on Gram-positive/Gram-negative bacteria and viable/damaged bacteria, and operational parameters. Principal component analysis (PCA) was subsequently applied to identify activated sludge abnormalities, allowing the identification of several disturbances, namely filamentous bulking, pinpoint flocs formation, and zoogleal bulking as well as normal conditions by grouping the collected... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294338 Sat, 08 Oct 2011 03:41:58 +0100 5294338 http://www.medworm.com/index.php?rid=5294337&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962367%26dopt%3DAbstract Authors: Cid FD, Antón RI, Pardo R, Vega M, Caviedes-Vidal E Abstract Temporal and spatial patterns of water quality of an important artificial water reservoir located in the semiarid Midwest of Argentina were investigated using chemometric techniques. Surface water samples were collected at 38 points of the water reservoir during eleven sampling campaigns between October 1998 and June 2000, covering the warm wet season and the cold dry season, and analyzed for dissolved oxygen (DO), conductivity, pH, ammonium, nitrate, nitrite, total dissolved solids (TDS), alkalinity, hardness, bicarbonate, chloride, sulfate, calcium, magnesium, fluoride, sodium, potassium, iron, aluminum, silica, phosphate, sulfide, arsenic, chromium, lead, cadmium, chemical oxygen demand (COD), biochemical oxy... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294337 Sat, 08 Oct 2011 03:41:48 +0100 5294337 http://www.medworm.com/index.php?rid=5294336&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962368%26dopt%3DAbstract Authors: Allen RC, Rutan SC Abstract Simulated and experimental data were used to measure the effectiveness of common interpolation techniques during chromatographic alignment of comprehensive two-dimensional liquid chromatography-diode array detector (LC×LC-DAD) data. Interpolation was used to generate a sufficient number of data points in the sampled first chromatographic dimension to allow for alignment of retention times from different injections. Five different interpolation methods, linear interpolation followed by cross correlation, piecewise cubic Hermite interpolating polynomial, cubic spline, Fourier zero-filling, and Gaussian fitting, were investigated. The fully aligned chromatograms, in both the first and second chromatographic dimensions, were analyzed by parallel fa... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294336 Sat, 08 Oct 2011 03:41:37 +0100 5294336 http://www.medworm.com/index.php?rid=5294335&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962369%26dopt%3DAbstract Authors: Dębska B, Guzowska-Świder B Abstract The determination of food quality, authenticity and the detection of adulterations are problems of increasing importance in food chemistry. Recently, chemometric classification techniques and pattern recognition analysis methods for wine and other alcoholic beverages have received great attention and have been largely used. Beer is a complex mixture of components: on one hand a volatile fraction, which is responsible for its aroma, and on the other hand, a non-volatile fraction or extract consisting of a great variety of substances with distinct characteristics. The aim of this study was to consider parameters which contribute to beer differentiation according to the quality grade. Chemical (e.g. pH, acidity, dry extract, alcohol cont... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294335 Sat, 08 Oct 2011 03:41:26 +0100 5294335 http://www.medworm.com/index.php?rid=5294334&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962370%26dopt%3DAbstract This article presents potential solutions to these challenges, including multiway analysis, object tracking, multivariate curve resolution and non-linear regression. Several real world examples of time series HCI data are presented to illustrate the proposed solutions. PMID: 21962370 [PubMed - in process] (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294334 Sat, 08 Oct 2011 03:41:15 +0100 5294334 http://www.medworm.com/index.php?rid=5294333&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962371%26dopt%3DAbstract Authors: Dębska B, Guzowska-Świder B Abstract Artificial neural network (ANN) classifiers have been successfully implemented for various quality inspection and grading tasks of diverse food products. ANN are very good pattern classifiers because of their ability to learn patterns that are not linearly separable and concepts dealing with uncertainty, noise and random events. In this research, the ANN was used to build the classification model based on the relevant features of beer. Samples of the same brand of beer but with varying manufacturing dates, originating from miscellaneous manufacturing lots, have been represented in the multidimensional space by data vectors, which was an assembly of 12 features (% of alcohol, pH, % of CO(2) etc.). The classification has been performed ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294333 Sat, 08 Oct 2011 03:41:04 +0100 5294333 http://www.medworm.com/index.php?rid=5294332&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962372%26dopt%3DAbstract In this study, three new SVR-PPRV methods are proposed, in which a possibility for decreasing the PLS model complexity during the variable reduction process is build in. Therefore we denote our methods as PPRVR-CAM methods (Predictive-Property-Ranked Variable Reduction with Complexity Adapted Models). The selective and predictive abilities of the new methods are investigated and tested, using the absolute PLS regression coefficients as predictive property. They were compared with two modifications of existing SVR-PPRV methods (with constant PLS model complexity) and with two reference methods: uninformative variable elimination followed by either a genetic algorithm for PLS (UVE-GA-PLS) or an interval PLS (UVE-iPLS). The performance of the methods is investigated in conjunction with two da... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294332 Sat, 08 Oct 2011 03:40:53 +0100 5294332 http://www.medworm.com/index.php?rid=5294331&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962373%26dopt%3DAbstract Authors: Chauvin B, Kasselouri A, Chaminade P, Quiameso R, Nicolis I, Maillard P, Prognon P Abstract Tetrapyrrole rings possess four nitrogen atoms, two of which act as Bröndsted bases in acidic media. The two protonation steps occur on a close pH range, particularly in the case of meso-tetraphenylporphyrin (TPP) derivatives. If the cause of this phenomenon is well known - a protonation-induced distortion of the porphyrin ring - data on stepwise protonation constants and on electronic absorption spectra of monoprotonated TPPs are sparse. A multivariate approach has been systematically applied to a series of glycoconjugated and hydroxylated TPPs, potential anticancer drugs usable in Photodynamic Therapy. The dual purpose was determination of protonation constants and linking substi... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294331 Sat, 08 Oct 2011 03:40:42 +0100 5294331 http://www.medworm.com/index.php?rid=5294330&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962374%26dopt%3DAbstract Authors: Drgan V, Kotnik D, Novič M Abstract Optimization procedure of gradient separations in ion-exchange chromatography using simplex optimization method in combination with the computer simulation program for ion-exchange chromatography is presented. The optimization of parameters describing gradient profile for the separation in ion chromatography is based on the optimization criterion obtained from calculated chromatograms. The optimization criterion depends on the parameters used for calculations and thus exhibits the quality of gradient conditions for the separation of the analytes. Simplex method is used to calculate new gradient profiles in order to reach optimum separations for the selected set of analytes. The Simplex algorithm works stepwise, for each new combination ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294330 Sat, 08 Oct 2011 03:40:32 +0100 5294330 http://www.medworm.com/index.php?rid=5294329&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962375%26dopt%3DAbstract Authors: Zuperl S, Fornasaro S, Novič M, Passamonti S Abstract The transport activity of a membrane protein, bilitranslocase (T.C. # 2.A.65.1.1), which acts as a transporter of bilirubin from blood to liver cells, was experimentally determined for a large set of various endogenous compounds, drugs, purine and pyrimidine derivatives. On these grounds, the structure-activity models were developed following the OECD principles of QSAR models and their predictive ability for new chemicals was evaluated. The applicability domain of the models was estimated by Euclidean distances criteria according to the applied modeling method. The selection of the most influential structural variables was an important stage in the adopted modeling methodology. The interpretation of selected variables... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294329 Sat, 08 Oct 2011 03:40:22 +0100 5294329 http://www.medworm.com/index.php?rid=5294328&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21962376%26dopt%3DAbstract Authors: Dégardin K, Roggo Y, Been F, Margot P Abstract Raman spectroscopy combined with chemometrics has recently become a widespread technique for the analysis of pharmaceutical solid forms. The application presented in this paper is the investigation of counterfeit medicines. This increasingly serious issue involves networks that are an integral part of industrialized organized crime. Efficient analytical tools are consequently required to fight against it. Quick and reliable authentication means are needed to allow the deployment of measures from the company and the authorities. For this purpose a method in two steps has been implemented here. The first step enables the identification of pharmaceutical tablets and capsules and the detection of their counterfeits. A nonlinear c... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5294328 Sat, 08 Oct 2011 03:40:12 +0100 5294328 http://www.medworm.com/index.php?rid=5225905&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889624%26dopt%3DAbstract Authors: Borman PJ, Chatfield MJ, Damjanov I, Jackson P Abstract This tutorial explains how well thought-out application of design and analysis methodology, combined with risk assessment, leads to improved assessment of method ruggedness. The authors define analytical method ruggedness as an experimental evaluation of noise factors such as analyst, instrument or stationary phase batch. Ruggedness testing is usually performed upon transfer of a method to another laboratory, however, it can also be employed during method development when an assessment of the method's inherent variability is required. The use of a ruggedness study provides a more rigorous method for assessing method precision than a simple comparative intermediate precision study which is typically performed as part o... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5225905 Sun, 18 Sep 2011 04:58:17 +0100 5225905 http://www.medworm.com/index.php?rid=5225904&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889625%26dopt%3DAbstract Authors: Armenta S, Alcala M, Blanco M Abstract The applications of ion mobility spectrometry (IMS) have grown exponentially beyond its uses for explosive, illicit drug and chemical warfare agent monitoring in recent years. Instrumental developments including new drift tube materials and ionization sources have enabled the manufacturing of more sophisticated and affordable IMS equipment for the advantageous analysis of samples with no pretreatment. The most recent applications of IMS include quality control and cleaning validation procedures in the pharmaceutical industry; determinations of contaminants in food samples; clinical analyses of biological fluids; environmental analyses of contaminants in gaseous, liquid and solid samples; and (bio)process quality control monitoring. Co... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5225904 Sun, 18 Sep 2011 04:58:07 +0100 5225904 http://www.medworm.com/index.php?rid=5225903&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889626%26dopt%3DAbstract This article aims to review the developments in the technologies behind commercial BGMD, especially those in the areas of chemistries, mediators and other components. The technology concerns, on-going developments and future trends in blood glucose monitoring (BGM) are also discussed. PMID: 21889626 [PubMed - in process] (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5225903 Sun, 18 Sep 2011 04:57:57 +0100 5225903 http://www.medworm.com/index.php?rid=5215941&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889627%26dopt%3DAbstract Authors: Ulusoy Hİ, Akçay M, Ulusoy S, Gürkan R Abstract Cloud point extraction (CPE) methodology has successfully been employed for the preconcentration of ultra-trace arsenic species in aqueous samples prior to hydride generation atomic absorption spectrometry (HGAAS). As(III) has formed an ion-pairing complex with Pyronine B in presence of sodium dodecyl sulfate (SDS) at pH 10.0 and extracted into the non-ionic surfactant, polyethylene glycol tert-octylphenyl ether (Triton X-114). After phase separation, the surfactant-rich phase was diluted with 2mL of 1M HCl and 0.5mL of 3.0% (w/v) Antifoam A. Under the optimized conditions, a preconcentration factor of 60 and a detection limit of 0.008μgL(-1) with a correlation coefficient of 0.9918 was obtained with a calibration curve i... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215941 Wed, 14 Sep 2011 00:15:42 +0100 5215941 http://www.medworm.com/index.php?rid=5215940&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889628%26dopt%3DAbstract Authors: Tarley CR, Andrade FN, de Oliveira FM, Corazza MZ, de Azevedo LF, Segatelli MG Abstract A novel ion imprinted polyvinylimidazole-silica hybrid copolymer (IIHC) was synthesized and used as a selective solid sorbent for Pb(2+) ions preconcentration using an on-line solid phase extraction (SPE) system coupled to TS-FF-AAS. The ionic hybrid sorbent was prepared using 1-vinylimidazole and 3-(trimethoxysilyl)propylmethacrylate as monomers, Pb(2+) ions as template, tetraethoxysilane as reticulating agent and 2,2'-azobis-isobutyronitrile as initiator. The best on-line SPE conditions concerning sorption behavior, including sample pH (6.46), buffer concentration (9.0mmolL(-1)), eluent (HNO(3)) concentration (0.5molL(-1)) and preconcentration flow rate (4.0mLmin(-1)), were optimized ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215940 Wed, 14 Sep 2011 00:15:21 +0100 5215940 http://www.medworm.com/index.php?rid=5215939&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889629%26dopt%3DAbstract The objectives of the study were to classify the sampling sites (spatial) and months (temporal) to group the similar ones in terms of water quality with a view to reduce their number; and to develop a suitable SVR model for predicting the biochemical oxygen demand (BOD) of water using a set of variables. The spatial and temporal SVC models rendered grouping of 10 monitoring sites and 12 sampling months into the clusters of 3 each with misclassification rates of 12.39% and 17.61% in training, 17.70% and 26.38% in validation, and 14.86% and 31.41% in test sets, respectively. The SVR model predicted water BOD values in training, validation, and test sets with reasonably high correlation (0.952, 0.909, and 0.907) with the measured values, and low root mean squared errors of 1.53, 1.44, and 1.3... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215939 Wed, 14 Sep 2011 00:15:01 +0100 5215939 http://www.medworm.com/index.php?rid=5215938&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889630%26dopt%3DAbstract In this study, a novel predictor (Methy_SVMIACO) based on support vector machine (SVM) and improved ant colony optimization algorithm (IACO) is developed to identify methylation sites. The IACO is utilized to find the optimal feature subset and parameter of SVM, while SVM is employed to perform the identification of methylation sites. Comparison of the IACO with conventional ACO shows that the IACO converges quickly toward the global optimal solution and it is more useful tool for feature selection and SVM parameter optimization. The performance of Methy_SVMIACO is evaluated with a sensitivity of 85.71%, a specificity of 86.67%, an accuracy of 86.19% and a Matthew's correlation coefficient (MCC) of 0.7238 for lysine as well as a sensitivity of 89.08%, a specificity of 94.07%, an accuracy o... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215938 Wed, 14 Sep 2011 00:14:43 +0100 5215938 http://www.medworm.com/index.php?rid=5215937&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889631%26dopt%3DAbstract Authors: Liu A, Geng H, Xu C, Qiu H Abstract Nanoporous copper (NPC) obtained by dealloying CuAl alloy is used as both three-dimensional template and reducing agent for the fabrication of nanoporous PdCu alloy with hollow ligaments by a simple galvanic replacement reaction with H(2)PdCl(4) aqueous solution. Electron microscopy and X-ray diffraction characterizations demonstrate that after the replacement reaction, the ligaments become hollow tubular structure and the ligament shell is also comprised of small pores and nanoparticles with a typical size of ∼4nm (third order porosity). The as-prepared nanotubular mesoporous PdCu alloy (NM-PdCu) structure exhibits remarkably improved electrocatalytic activity towards the oxidation of formic acid and H(2)O(2) compared with nanoporous ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215937 Wed, 14 Sep 2011 00:14:23 +0100 5215937 http://www.medworm.com/index.php?rid=5215936&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889632%26dopt%3DAbstract Authors: Ali K, Maltese F, Fortes AM, Pais MS, Verpoorte R, Choi YH Abstract Although metabolomics aims at profiling all the metabolites in organisms, data quality is quite dependent on the pre-analytical methods employed. In order to evaluate current methods, different pre-analytical methods were compared and used for the metabolic profiling of grapevine as a model plant. Five grape cultivars from Portugal in combination with chemometrics were analyzed in this study. A common extraction method with deuterated water and methanol was found effective in the case of amino acids, organic acids, and sugars. For secondary metabolites like phenolics, solid phase extraction with C-18 cartridges showed good results. Principal component analysis, in combination with NMR spectroscopy, was app... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215936 Wed, 14 Sep 2011 00:14:02 +0100 5215936 http://www.medworm.com/index.php?rid=5215935&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889633%26dopt%3DAbstract Authors: Gao Y, Zhang H, Chen J, Zhang Q, Tian Y, Qi P, Yu Z Abstract The performances of three adsorbents, i.e. silica gel, neutral and basic alumina, in the separation of short chain polychlorinated n-alkanes (sPCAs) from potential interfering substances such as polychlorinated biphenyls (PCBs) and organochlorine pesticides were evaluated. To increase the cleanup efficiency, a two-step cleanup method using silica gel column and subsequent basic alumina column was developed. All the PCB and organochlorine pesticides could be removed by this cleanup method. The very satisfying cleanup efficiency of sPCAs has been achieved and the recovery in the cleanup method reached 92.7%. The method detection limit (MDL) for sPCAs in sediments was determined to be 14ngg(-1). Relative standard de... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215935 Wed, 14 Sep 2011 00:13:39 +0100 5215935 http://www.medworm.com/index.php?rid=5215934&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889634%26dopt%3DAbstract Authors: Wall MJ, Crowell AM, Simms GA, Liu F, Doucette AA Abstract For bottom-up MS, the digestion step is critical and is typically performed with trypsin. Solvent-assisted digestion in 80% acetonitrile has previously been shown to improve protein sequence coverage at shorter digestion times. This has been attributed to enhanced enzyme digestion efficiency in this solvent. However, our results demonstrate that tryptic digestion in 80% acetonitrile is less efficient than that of conventional (aqueous) digestion. This is a consequence of decreased enzyme activity beyond ∼40% acetonitrile, increased enzyme autolysis and lower protein solubility in 80% acetonitrile. We observe multiple missed cleavages and reduced concentration of fully cleaved digestion products. Nonetheless we co... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215934 Wed, 14 Sep 2011 00:13:12 +0100 5215934 http://www.medworm.com/index.php?rid=5215933&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889635%26dopt%3DAbstract In this study, we demonstrated that the unbiased non-targeted analysis based on metabolomic approach allows the identification of key volatile compounds related to beef flavor in GSH-MRPs. PMID: 21889635 [PubMed - in process] (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215933 Wed, 14 Sep 2011 00:12:40 +0100 5215933 http://www.medworm.com/index.php?rid=5215932&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889636%26dopt%3DAbstract Authors: Carrillo-Carrión C, Simonet BM, Valcárcel M Abstract Assemblies of closed nanoparticles have focused interest because they exhibit new optical and chemical properties. The use of a 1D covalent strategy for quantum dots-assemblies has been proposed in this work as novelty. It was studied the effect of use different dithiols, including aromatic and aliphatic dithiol compounds, on the formation of QDs-assemblies in order to establish the influence of the linker's structure on the geometry of the assemblies, and hence on their properties. As a second part of the work, the changes on analytical response to analytes thanks to the formation of QDs-assemblies when dithiols are added were studied for firs time. For this study, some biogenic amines were selected as target analytes... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215932 Wed, 14 Sep 2011 00:12:18 +0100 5215932 http://www.medworm.com/index.php?rid=5215931&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889637%26dopt%3DAbstract Authors: Wei G, Yin J, Ma X, Yu S, Wei D, Du Y Abstract A new fluorescent probe for the detection of F(-) (TBA(+) and Na(+) salts) has been developed, which is based on a desilylation triggered chromogenic reaction in water. This probe exhibits excellent F(-) ion selectivity as well as significant color changes visible to the naked eye at the concentration of 1.5mgL(-1), the WHO recommended level of F(-) ions in drinking water. This new carbohydrate modified probe can be used directly in aqueous medium without using organic co-solvents. Furthermore, the probe presents high sensitivity and selectivity for the imaging of F(-) ions in HepG2 cells. PMID: 21889637 [PubMed - in process] (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215931 Wed, 14 Sep 2011 00:11:55 +0100 5215931 http://www.medworm.com/index.php?rid=5215930&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889638%26dopt%3DAbstract Authors: Ng SM, Narayanaswamy R Abstract Despite the increasing number of usage of molecularly imprinted polymers (MIPs) in optical sensor application, the correlation between the analytical signals and the binding isotherms has yet to be fully understood. This work investigates the relationship between the signals generated from MIPs sensors to its respective binding affinity variables generated using binding isotherm models. Two different systems based on the imprinting of metal ion and organic compound have been selected for the study, which employed reflectance and fluorescence sensing schemes, respectively. Batch binding analysis using the standard binding isotherm models was employed to evaluate the affinity of the binding sites. Evaluation using the discrete bi-Langmuir isot... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215930 Wed, 14 Sep 2011 00:11:25 +0100 5215930 http://www.medworm.com/index.php?rid=5215929&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889639%26dopt%3DAbstract Authors: Liron Z, Zifman A, Heleg-Shabtai V Abstract A new sensitive surface-enhanced Raman scattering (SERS) assay for detection of cholinesterase inhibitors such as organophosphorous pesticides using silver colloidal nanoparticles was developed and optimized. Acetylcholinesterase (AChE) mediated the hydrolysis of acetylthiocholine to produce thiocholine, which interacted with the silver nanoparticles to give a specific SERS spectrum. Variation in enzyme activity due to inhibition was measured from changes in intensity of a characteristic peak (772cm(-1)) of the SERS spectrum that was directly correlated with the concentration of produced thiocholine. The method was demonstrated for the detection of paraoxon as reference AChE inhibitor. Limit of detection of paraoxon for 5min incu... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215929 Wed, 14 Sep 2011 00:10:56 +0100 5215929 http://www.medworm.com/index.php?rid=5215928&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889640%26dopt%3DAbstract Authors: Stringer RC, Gangopadhyay S, Grant SA Abstract A comparative study was conducted to study the effects that two different polymerization solvents would have on the properties of imprinted polymer microparticles prepared using precipitation polymerization. Microparticles prepared in chloroform, which previous results indicated was the optimal solvent for molecular imprinting of nitroaromatic explosive compounds, were compared to water, which was hypothesized to decrease water swelling of the polymer and allow enhanced rebinding of aqueous template. The microparticles were characterized and were integrated into a fluorescence sensing mechanism for detection of nitroaromatic explosive compounds. The performance of the sensing mechanisms was compared to illustrate which polymer... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215928 Wed, 14 Sep 2011 00:10:34 +0100 5215928 http://www.medworm.com/index.php?rid=5215927&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889641%26dopt%3DAbstract Authors: Shock D, Dennis GR, Guiochon G, Dasgupta PK, Shalliker RA Abstract A two-dimensional (2-D) "heart-cutting" HPLC system was used to fractionate oligostyrenes into the respective diastereoisomers. For samples of known composition, the response of an ultraviolet (UV) absorbance detector followed the anticipated pattern. The response of an evaporative light-scattering (ELSD) detector on the other hand indicated quite different concentrations for the two diastereoisomers, relative to what was anticipated and what was indicated by the UV detector. Whereas approximately the same concentration was indicated by UV, ELSD in some cases indicated no detection of the later eluting isomer. The magnitude of the errors depended on both the molecular weight and the tacticity of the diaster... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215927 Wed, 14 Sep 2011 00:10:12 +0100 5215927 http://www.medworm.com/index.php?rid=5215926&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889642%26dopt%3DAbstract Authors: Cao Q, Yin Y, Quan L, Li N, Li K, Liu F Abstract Multi-hydroxyl amines including tris(hydroxymethyl)aminomethane (Tris), serinol and ethanolamine were selected as weak affinity ligands using a rapid screening by quartz crystal microbalance (QCM) biosensor. Based on the specific recognition between the ligands and two proteins, lysozyme (LZM) and cytochrome c (Cyt c), a weak affinity chromatography method was developed for specific separation of the two proteins. The frontal analysis results showed that the apparent dissociation constants (K(D)) of ligand-protein complexes were all in the order of weak affinity (10(-4)M). By weak affinity columns modified with the three multi-hydroxyl amines individually, LZM and Cyt c were baseline separated as retarded peaks from non-spec... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215926 Wed, 14 Sep 2011 00:09:49 +0100 5215926 http://www.medworm.com/index.php?rid=5215925&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889643%26dopt%3DAbstract Authors: Song L, Guo Z, Chen Y Abstract A fast, simple and cost-effective one-pot labeling strategy coupled with capillary zone electrophoresis was developed for the complete separation of amino acid mixture. The strategy includes two steps of reactions: Cyanuric chloride was made to react first with 7-amino-1,3-naphthalenedisulfonic acid monopotassium salt at 0°C for 10min, and then with amino acids at 55°C for 6min. The resulted products, after diluted with water, were injected into capillary zone electrophoresis system for separation. Using a running buffer of 20mM sodium tetraborate decahydrate at pH 10.1, nineteen amino acids were efficiently separated in 25min, with relative standard deviation of 0.36-1.6% and 0.96-2.1% (within and between days, respectively) for migration ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215925 Wed, 14 Sep 2011 00:09:27 +0100 5215925 http://www.medworm.com/index.php?rid=5215924&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907017%26dopt%3DAbstract Authors: Hou S, Wentzell PD Abstract As a powerful method for exploratory data analysis, projection pursuit (PP) often outperforms principal component analysis (PCA) to discover important data structure. PP was proposed in 1970s but has not been widely used in chemistry largely because of the difficulty in the optimization of projection indices. In this work, new algorithms, referred as "quasi-power methods", are proposed to optimize kurtosis as a projection index. The new algorithms are simple, fast, and stable, which makes the search for the global optimum more efficient in the presence of multiple local optima. Maximization of kurtosis is helpful in the detection of outliers, while minimization tends to reveal clusters in the data, so the ability to search separately for the max... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215924 Wed, 14 Sep 2011 00:09:06 +0100 5215924 http://www.medworm.com/index.php?rid=5215923&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907018%26dopt%3DAbstract Authors: Su M, Wei W, Liu S Abstract A comprehensive review on the development of analytical methods, by coupling electrochemiluminescence (ECL) detection with capillary electrophoresis (CE) and microchip electrophoresis (ME), is presented. After the description of the basic mechanism of ECL, the addition mode of luminescence reagent in CE-ECL system has been discussed. The analytical applications of the CE-ECL technique in terms of different analytes are also given. Due to the importance of ME as a separation method for the present and future, the ME detection methods based on ECL are considered in a relatively detailed way. Finally, possible trends for CE/ME-ECL in the near future are discussed. PMID: 21907018 [PubMed - in process] (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215923 Wed, 14 Sep 2011 00:08:45 +0100 5215923 http://www.medworm.com/index.php?rid=5215922&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907019%26dopt%3DAbstract Authors: Aufartová J, Mahugo-Santana C, Sosa-Ferrera Z, Santana-Rodríguez JJ, Nováková L, Solich P Abstract Residues of steroid hormones have become a cause for concern because they can affect the biological activity of non-target organisms. Steroid hormones are a potential risk for wildlife and humans through the consumption of contaminated food or water. Their determination requires extraction and clean-up steps, prior to detection, to reach low concentration levels. In recent years, a great effort has been made to develop new analytical methodologies, such as microextraction techniques, that reduce environmental pollution. Researchers have modified old methods to incorporate procedures that use less-hazardous chemicals or that use smaller amounts of them. They are able to do... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215922 Wed, 14 Sep 2011 00:08:24 +0100 5215922 http://www.medworm.com/index.php?rid=5215921&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907020%26dopt%3DAbstract Authors: Bocklitz T, Walter A, Hartmann K, Rösch P, Popp J Abstract Raman spectroscopy in combination with chemometrics is gaining more and more importance for answering biological questions. This results from the fact that Raman spectroscopy is non-invasive, marker-free and water is not corrupting Raman spectra significantly. However, Raman spectra contain despite Raman fingerprint information other contributions like fluorescence background, Gaussian noise, cosmic spikes and other effects dependent on experimental parameters, which have to be removed prior to the analysis, in order to ensure that the analysis is based on the Raman measurements and not on other effects. Here we present a comprehensive study of the influence of pre-processing procedures on statistical models. We w... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215921 Wed, 14 Sep 2011 00:08:04 +0100 5215921 http://www.medworm.com/index.php?rid=5215920&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907021%26dopt%3DAbstract Authors: Hemmateenejad B, Shamsipur M, Zare-Shahabadi V, Akhond M Abstract The classification and regression trees (CART) possess the advantage of being able to handle large data sets and yield readily interpretable models. A conventional method of building a regression tree is recursive partitioning, which results in a good but not optimal tree. Ant colony system (ACS), which is a meta-heuristic algorithm and derived from the observation of real ants, can be used to overcome this problem. The purpose of this study was to explore the use of CART and its combination with ACS for modeling of melting points of a large variety of chemical compounds. Genetic algorithm (GA) operators (e.g., cross averring and mutation operators) were combined with ACS algorithm to select the best solutio... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215920 Wed, 14 Sep 2011 00:07:47 +0100 5215920 http://www.medworm.com/index.php?rid=5215919&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907022%26dopt%3DAbstract Authors: Langmaier J, Garay F, Kivlehan F, Chaum E, Lindner E Abstract 2,6-Diisopropylphenol (propofol) is a potent anesthetic drug with fast onset of the anesthetic effect and short recovery time for the patients. Outside of the United States, propofol is widely used in performing target controlled infusion anesthesia. With the long term vision of an electrochemical sensor for in vivo monitoring and feedback controlled dosing of propofol in blood, different alternatives for the electrochemical quantification of propofol using diverse working electrodes and experimental conditions are presented in this contribution. When the electrochemical oxidation of propofol takes place on a glassy carbon working electrode, an electrochemically active film grows on the electrode surface. The re... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215919 Wed, 14 Sep 2011 00:07:31 +0100 5215919 http://www.medworm.com/index.php?rid=5215918&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907023%26dopt%3DAbstract Authors: Song W, Ding J, Liang R, Qin W Abstract A polymeric membrane permanganate-selective electrode has been developed as a current-controlled reagent release system for potentiometric detection of reductants in flow injection analysis. By applying an external current, diffusion of permanganate ions across the polymeric membrane can be controlled precisely. The permanganate ions released at the sample-membrane interface from the inner filling solution of the electrode are consumed by reaction with a reductant in the sample solution thus changing the measured membrane potential, by which the reductant can be sensed potentiometrically. Ascorbate, dopamine and norepinephrine have been employed as the model reductants. Under the optimized conditions, the potential peak heights are p... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215918 Wed, 14 Sep 2011 00:07:16 +0100 5215918 http://www.medworm.com/index.php?rid=5215917&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907024%26dopt%3DAbstract Authors: Khamjumphol U, Watchasit S, Suksai C, Janrungroatsakul W, Boonchiangma S, Tuntulani T, Ngeontae W Abstract Fabrication of PVC membrane electrodes incorporating selective neutral carriers for Cd(2+) was reported. The ionophores were designed to have different topologies, donor atoms and lipophilicity by attaching tripodal amine (TPA) units to the lipophilic anthracene (ionophore I) and p-tert-butylcalix[4]arene (ionophores II, III and IV). The synthesized ionophores were incorporated to the plasticized PVC membranes to prepare Cd(II) ion selective electrodes (ISEs). The membrane electrodes were optimized by changing types and amounts of ionic sites and plasticizers. The selectivity of the membranes fabricated from the synthesized ionophores was evaluated, the relationship b... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215917 Wed, 14 Sep 2011 00:07:01 +0100 5215917 http://www.medworm.com/index.php?rid=5215916&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907025%26dopt%3DAbstract Authors: Cervera MI, Beltran J, Lopez FJ, Hernandez F Abstract In the present work, a rapid method with little sample handling has been developed for determination of 23 selected volatile organic compounds in environmental and wastewater samples. The method is based on headspace solid-phase microextraction (SPME) followed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) determination using triple quadrupole analyzer (QqQ) in electron ionization mode. The best conditions for extraction were optimised with a factorial design taking into account the interaction between different parameters and not only individual effects of variables. In the optimized procedure, 4mL of water sample were extracted using a 10mL vial and adding 0.4g NaCl (final NaCl content of 10%). A... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215916 Wed, 14 Sep 2011 00:06:46 +0100 5215916 http://www.medworm.com/index.php?rid=5215915&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907026%26dopt%3DAbstract Authors: Zhang R, Li N, Wang C, Bai Y, Ren R, Gao S, Yu W, Zhao T, Zhang H Abstract The foaming property of ionic liquids (ILs) was found and the factors that can influence foamability of the ILs were investigated. Based on the property of the ILs, the foam floatation-solid phase extraction (FF-SPE) was developed. The IL-based FF-SPE was applied to the extraction and concentration of steroid hormones, including corticosterone, 17-β-estadiol, 17-α-estradiol, 19-nortestosterone, estrone, testosterone, 17-α-hydroxyprogesterone, medroxyprogesterone, chloromadinon 17-acetate, norethisterone acetate, medroxyprogesterone-17-acetate, progesterone, 17-β-estradiol 3-benzoate and testosteron 17-propionate in water samples and then the steroid hormones were determined by high-performance l... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215915 Wed, 14 Sep 2011 00:06:33 +0100 5215915 http://www.medworm.com/index.php?rid=5215914&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907027%26dopt%3DAbstract Authors: Zamora-Ros R, Rabassa M, Cherubini A, Urpi-Sarda M, Llorach R, Bandinelli S, Ferrucci L, Andres-Lacueva C Abstract Polyphenols have beneficial effects on several chronic diseases but assessing polyphenols intake from self-reported dietary questionnaires tends to be inaccurate and not very reliable. A promising alternative is to use urinary excretion of polyphenols as a proxy measure of intake. The best method to assess urinary excretion is to collect 24-h urine. However, since collecting 24-h urine method is expensive, time consuming and may be difficult to implement in large population-based studies, measures obtained from spot urine normalized by creatinine are commonly used. The purpose of the study was to evaluate the correlation between polyphenols dietary intake and ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215914 Wed, 14 Sep 2011 00:06:19 +0100 5215914 http://www.medworm.com/index.php?rid=5215913&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907028%26dopt%3DAbstract Authors: Gentle BS, Ellis PS, Grace MR, McKelvie ID Abstract Second derivative ultra-violet spectrophotometric methods are described for the measurement of nitrate and total nitrogen in freshwaters using flow analysis techniques. A simple flow system consisting of a peristaltic pump and a single-reflection flow-through cell was used for the measurement of nitrate. Quantification of total nitrogen using alkaline peroxodisulfate photo-digestion was achieved by incorporating an ultra-violet photo-reactor, a hollow-fibre filter and a debubbler into the flow system. The nitrate system featured a limit of detection of 0.04mgNL(-1), 0.4%RSD (1mgNL(-1) as nitrate, n=10), a coefficient of determination (R(2)) of 0.9995 over the calibration range 0.0-2.0mgNL(-1), and a data acquisition time ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215913 Wed, 14 Sep 2011 00:06:06 +0100 5215913 http://www.medworm.com/index.php?rid=5215912&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907029%26dopt%3DAbstract Authors: Míguez-Framil M, Moreda-Piñeiro A, Bermejo-Barrera P, Cocho JÁ, Tabernero MJ, Bermejo AM Abstract A fast and highly sensitive electrospray ionization tandem mass spectrometry (ESI-MS/MS) method has been developed for the simultaneous determination of morphine, 6-methylacetylmorphine (6-MAM), codeine, cocaine and benzoylecgonine (BZE) in hair from drug abusers. Pulverized hair samples were subjected to an optimized matrix solid phase dispersion (MSPD) procedure with alumina, followed by diluted hydrochloric acid elution on column solid-phase extraction (SPE) clean-up/pre-concentration. Alternatively, samples were also subjected to an optimized ultrasound assisted enzymatic hydrolysis (USEH) with Pronase E, followed by an off-line SPE clean up/pre-concentration procedure.... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215912 Wed, 14 Sep 2011 00:05:52 +0100 5215912 http://www.medworm.com/index.php?rid=5215911&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907030%26dopt%3DAbstract Authors: Gao H, Qi X, Chen Y, Sun W Abstract An electrochemical DNA biosensor was fabricated by self-assembling probe single-stranded DNA (ssDNA) with a nanogold decorated on ionic liquid modified carbon paste electrode (IL-CPE). IL-CPE was fabricated using 1-butylpyridinium hexafluorophosphate as the binder and the gold nanoparticles were electrodeposited on the surface of IL-CPE (Au/IL-CPE). Then mercaptoacetic acid was self-assembled on the Au/IL-CPE to obtain a layer of modified film, and the ssDNA probe was further covalently-linked with mercaptoacetic acid by the formation of carboxylate ester with the help of N-(3-dimethylamino-propyl)-N'-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide. The hybridization reaction with the target ssDNA was monitored with methylene bl... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215911 Wed, 14 Sep 2011 00:05:40 +0100 5215911 http://www.medworm.com/index.php?rid=5215910&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907031%26dopt%3DAbstract Authors: Strömberg N, Hakonen A Abstract A plasmophore sensitized optode was developed for imaging ammonia (NH(3)) concentrations in muscle tissues. The developed ammonia sensor and an equivalent non plasmophore version of the sensor were tested side by side to compare their limit of detection, dynamic range, reversibility and overall imaging quality. Bio-degradation patterns of ammonia release from lean porcine skeletal muscle were studied over a period of 11 days. We demonstrate that ammonia concentrations ranging from 10nM can be quantified reversibly with an optical resolution of 127μm in a sample area of 25mm×35mm. The plasmophore ammonia optode showed improved reversibility, less false pixels and a 2nM ammonia detection limit compared to 200nM for the non-plasmophore senso... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215910 Wed, 14 Sep 2011 00:05:26 +0100 5215910 http://www.medworm.com/index.php?rid=5215909&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907032%26dopt%3DAbstract Authors: Eskandari H, Shariati MR Abstract A new method was proposed for the determination of ammonium based on the preconcentration with dodecylbenzene sulfonate modified magnetite nanoparticles. Ammonium was oxidized to nitrite by hypobromite and then the nitrite produced was determined spectrophotometrically, using sulfabenzamide and N-(1-naphthyl) ethylenediamine after solid phase extraction. The azo dye produced was desorbed by an appropriate small volume of sodium hydroxide prior to the absorbance measurement. The linear calibration graphs were obtained in the concentration range of 0.03-6.00ngmL(-1) ammonium. The relative standard deviation and recovery percents were 1.0 and 99.0, respectively, for 1.0ngmL(-1) ammonium, and the limit of detection was 3.2ngL(-1) ammonium. The... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215909 Wed, 14 Sep 2011 00:05:14 +0100 5215909 http://www.medworm.com/index.php?rid=5215908&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907033%26dopt%3DAbstract Authors: van Wyk PH, Gerber WJ, Koch KR Abstract A robust reversed phase ion-pairing RP-HPLC method has been developed for the unambiguous speciation and quantification of all possible homoleptic and heteroleptic octahedral platinum(IV) [PtCl(6-n)Br(n)](2-) (n=0-6) as well as the corresponding platinum(II) [PtCl(4-n)Br(n)](2-) (n=0-4) complex anions using UV/Vis detection. High resolution (195)Pt NMR in more concentrated solutions of these Pt(II/IV) complexes (≥50mM) served to validate the chromatographic peak assignments, particularly in the case of the possible stereoisomers of Pt(II/IV) complex anions. By means of IP-RP-HPLC coupled to ICP-MS or ICP-OES it is possible to accurately determine the relative concentrations of all possible Pt(II/IV) species in these solutions, whic... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215908 Wed, 14 Sep 2011 00:05:02 +0100 5215908 http://www.medworm.com/index.php?rid=5215907&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907034%26dopt%3DAbstract In this study we improved the dansylacetamidooxyamine (DNSAOA)-LC-fluorescence method for the determination of aqueous-phase glyoxal (GL), methylglyoxal (MG) and hydroxyacetaldehyde (HA). As derivatization of dicarbonyls can potentially lead to complex mixtures, a thorough study of the reaction patterns of GL and MG with DNSAOA was carried out. Derivatization of GL and MG was shown to follow the kinetics of successive reactions, yielding predominantly doubly derivatized compounds. We verified that the bis-DNSAOA structure of these adducts exerted only minor influence on their fluorescence properties. Contrary to observations made with formaldehyde, derivatization of GL, MG and, to a lesser extent of HA, was shown to be faster in acidic (H(2)SO(4)) medium with a maximum of efficiency for ac... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215907 Wed, 14 Sep 2011 00:04:48 +0100 5215907 http://www.medworm.com/index.php?rid=5215906&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907035%26dopt%3DAbstract Authors: Gholivand MB, Abolghasemi MM, Fattahpour P Abstract A highly porous fiber coated polypyrrole/hexagonally ordered silica (PPy/SBA15) materials were prepared for solid-phase microextraction (SPME). The PPy/SBA15 nanocomposite was synthesized by an in situ polymerization technique. The resulting material was characterized by the scanning electron microscopy, thermogravimetric analysis and differential thermal analysis. The prepared nanomaterial was immobilized onto a stainless steel wire for fabrication of the SPME fiber. The fiber was evaluated for the extraction of some polycyclic aromatic hydrocarbons (PAHs) from aqueous sample solutions in combination with gas chromatography-mass spectrometry (GC-MS). A one at-the-time optimization strategy was applied for optimizing the ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215906 Wed, 14 Sep 2011 00:04:34 +0100 5215906 http://www.medworm.com/index.php?rid=5215905&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907036%26dopt%3DAbstract Authors: Fredriksson MJ, Petersson P, Axelsson BO, Bylund D Abstract A strategy for rapid optimization of liquid chromatography column temperature and gradient shape is presented. The optimization as such is based on the well established retention and peak width models implemented in software like e.g. DryLab and LC simulator. The novel part of the strategy is a highly automated processing algorithm for detection and tracking of chromatographic peaks in noisy liquid chromatography-mass spectrometry (LC-MS) data. The strategy is presented and visualized by the optimization of the separation of two degradants present in ultraviolet (UV) exposed fluocinolone acetonide. It should be stressed, however, that it can be utilized for LC-MS analysis of any sample and application where severa... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5215905 Wed, 14 Sep 2011 00:04:18 +0100 5215905 http://www.medworm.com/index.php?rid=5139487&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819855%26dopt%3DAbstract We describe and compare the underlying principles of operation, ionization processes, detecting mass ranges, sensitivity, and representative applications of these techniques. PMID: 21819855 [PubMed - in process] (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139487 Fri, 19 Aug 2011 12:07:23 +0100 5139487 http://www.medworm.com/index.php?rid=5139486&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819856%26dopt%3DAbstract Authors: Shelor CP, Dasgupta PK Abstract Iodine is an essential element of human nutrition. Nearly a third of the global population has insufficient iodine intake and is at risk of developing Iodine Deficiency Disorders (IDD). Most countries have iodine supplementation and monitoring programs. Urinary iodide (UI) is the biomarker used for epidemiological studies; only a few methods are currently used routinely for analysis. These methods either require expensive instrumentation with qualified personnel (inductively coupled plasma-mass spectrometry, instrumental nuclear activation analysis) or oxidative sample digestion to remove potential interferences prior to analysis by a kinetic colorimetric method originally introduced by Sandell and Kolthoff ∼75 years ago. The Sandell-Kolth... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139486 Fri, 19 Aug 2011 12:07:18 +0100 5139486 http://www.medworm.com/index.php?rid=5139485&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819857%26dopt%3DAbstract Authors: Liu T, Nicholls IA, Oberg T Abstract Theoretical and experimental quantitative structure-retention relationships (QSRR) models are useful for characterizing solvent properties and column selectivity in reversed phase liquid chromatography (RPLC). The chromatographic behavior of a model analyte, the herbicide atrazine, in a system derived from nine organic solvents and three chromatographic columns was used for developing QSRR models. Multiple linear regression (MLR) and partial least squares regression (PLSR) were used as statistical approaches. The similarities and differences between linear solvation energy relationships (LSER), and semi-empirical and theoretical molecular models were demonstrated. QSRR models show high predictive power, and can successfully predict rete... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139485 Fri, 19 Aug 2011 12:07:14 +0100 5139485 http://www.medworm.com/index.php?rid=5139484&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819858%26dopt%3DAbstract Authors: Ylinen-Hinkka T, Niskanen AJ, Franssila S, Kulmala S Abstract C-reactive protein (CRP) was determined in the concentration range 0.01-10mgL(-1) using hot electron induced electrochemiluminescence (HECL) with devices combining both working and counter electrodes and sample confinement on a single chip. The sample area on the electrodes was defined by a hydrophobic ring, which enabled dispensing the reagents and the analyte directly on the electrode. Immunoassay of CRP by HECL using integrated electrodes is a good candidate for a high-sensitivity point-of-care CRP-test, because the concentration range is suitable, miniaturisation of the measurement system has been demonstrated and the assay method with integrated electrodes is easy to use. High-sensitivity CRP tests can be u... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139484 Fri, 19 Aug 2011 12:07:10 +0100 5139484 http://www.medworm.com/index.php?rid=5139483&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819859%26dopt%3DAbstract Authors: Gao Z, Ma X Abstract A novel approach for preconcentration and speciation analysis of trace amount of mercury from water samples was proposed by dispersive liquid-liquid microextraction (DLLME) coupled to high performance liquid chromatography with diode array detection (HPLC-DAD). Mercury species (Hg(2+), methylmercury (MeHg(+)) and phenylmercury (PhHg(+))) were complexed with dithizone (DZ) to form hydrophobic chelates and then extracted into the fine drops of extraction solvent dispersed in the aqueous sample by dispersive solvent. After extraction, the sedimented phase was analyzed by HPLC-DAD. Some important parameters affecting the DLLME such as extraction solvent and dispersive solvent type and volume, concentration of dithizone solution, sample pH, extraction time ... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139483 Fri, 19 Aug 2011 12:07:05 +0100 5139483 http://www.medworm.com/index.php?rid=5139482&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819860%26dopt%3DAbstract In this study, we investigated the use of hollow-fiber microdialysis (MD) sampling coupled on-line with high-performance liquid chromatography (HPLC) as an alternative to sample pretreatment for the direct determination of MEL and its analogue cyanuric acid (CYA) in NDC. After MD sampling, the dialysate was injected on-line into the chromatographic system for analysis of MEL and CYA with UV detection at 203nm. We monitored the effects of various parameters affecting the MD efficiency, namely the characteristics of the MD probe membrane, the flow-rate and the nature of the polarity modifier in the perfusion stream, and the addition of salt in the sample solution. The optimal enrichment efficiency for collecting MEL and CYA from aqueous NDC samples occurred with MD sampling using a hollow po... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139482 Fri, 19 Aug 2011 12:07:01 +0100 5139482 http://www.medworm.com/index.php?rid=5139481&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819861%26dopt%3DAbstract Authors: Ripollés C, Pitarch E, Sancho JV, López FJ, Hernández F Abstract In this work, we have developed a sensitive method for detection and quantification of eight N-nitrosamines, N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMor), N-nitrosomethylethylamine (NMEA), N-nitrosopirrolidine (NPyr), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPip), N-nitroso-n-dipropylamine (NDPA) and N-nitrosodi-n-butylamine (NDBA) in drinking water. The method is based on liquid chromatography coupled to tandem mass spectrometry, using atmospheric pressure chemical ionization (APCI) in positive mode with a triple quadrupole analyzer (QqQ). The simultaneous acquisition of two MS/MS transitions in selected reaction monitoring mode (SRM) for each compound, together with the evaluation... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139481 Fri, 19 Aug 2011 12:06:57 +0100 5139481 http://www.medworm.com/index.php?rid=5139480&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819862%26dopt%3DAbstract Authors: Czarnecki MA Abstract Sign of two-dimensional (2D) correlation peaks provides information on sequence of spectral events. This information is related to molecular mechanism of changes in a given system. Recently, few papers addressing the problems with interpretation of the sign of 2D correlation peaks have been published. To overcome these problems, a modification of the generalized 2D correlation method has been proposed. This method compares variations in the dynamic spectrum with a linear change at a reference point. The rates of spectral responses at individual wavenumbers are proportional to magnitudes of the peaks in the slice of asynchronous spectrum at the reference point. This way, analysis of complex 2D contour plots is replaced by a simple examination of one-di... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139480 Fri, 19 Aug 2011 12:06:53 +0100 5139480 http://www.medworm.com/index.php?rid=5139479&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819863%26dopt%3DAbstract Authors: Zhou Z, Li N, Tong A Abstract A highly selective and sensitive coumarin-based chemodosimeter 1 for Cu(2+) in water is reported in this work. 1 was designed and facilely synthesized by a one-step reaction with coumarin as a fluorophore and 2-picolinic acid as the binding moiety, which showed very week fluorescence in buffer solution, and its fluorescence was considerably enhanced by the addition of Cu(2+) at room temperature in 5min. Mechanism study suggested that Cu(2+) promoted the hydrolysis of 1 via the catalytic sensing cycle, generating a highly fluorescent product 7-hydroxycoumarin with fluorescence signal greatly amplified. The probe exhibited remarkably selective fluorescence enhancement to Cu(2+) over other metal ions at 454nm, with a detection limit of 35nM Cu(2+... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139479 Fri, 19 Aug 2011 12:06:49 +0100 5139479 http://www.medworm.com/index.php?rid=5139478&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819864%26dopt%3DAbstract In this study, an approach for screening and identification compounds with cardioprotective activity from medicinal plant extracts by cellular-fluorescence imaging technique was developed. It is a cell-based assay for measuring mitochondrial membrane potential changes in H9c2 cardiac muscle cells exposed to H(2)O(2) by using a fluorescence automatic microscopy screening platform. Rhodamine 123 was used as the fluorescent dye to indicate the change of mitochondrial membrane potential. The sensitivity and linear range of the proposed approach were evaluated and validated using vitamin C, an antioxidative compound. The method was applied to screen active components with potent cardioprotective effects from a traditional Chinese formula. The potential cardioprotective components were identifie... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139478 Fri, 19 Aug 2011 12:06:45 +0100 5139478 http://www.medworm.com/index.php?rid=5139477&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819865%26dopt%3DAbstract Authors: Sun Z, Jin L, Zhang S, Shi W, Pu M, Wei M, Evans DG, Duan X Abstract A novel optical chemosensor was fabricated based on 1-amino-8-naphthol-3,6-disulfonic acid sodium (H-acid) intercalated layered double hydroxide (LDH) film via the electrophoretic deposition (EPD) method. The film of H-acid/LDH with the thickness of 1μm possesses a well c-orientation of the LDH microcrystals confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The fluorescence detection for Hg(II) in aqueous solution was performed by using the H-acid/LDH film sensor at pH 7.0, with a linear response range in 1.0×10(-7) to 1.0×10(-5)molL(-1) and a detection limit of 6.3×10(-8)molL(-1). Furthermore, it exhibits excellent selectivity for Hg(II) over a large number of competitive c... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139477 Fri, 19 Aug 2011 12:06:41 +0100 5139477 http://www.medworm.com/index.php?rid=5139476&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819866%26dopt%3DAbstract Authors: Zhao H, Nan T, Tan G, Gao W, Cao Z, Sun S, Li Z, Li QX, Wang B Abstract Availability of highly sensitive assays for metal ions can help monitor and manage the environmental and food contamination. In the present study, a monoclonal antibody against Copper(II)-ethylenediaminetetraacetic acid was used to develop two sensitive ELISAs for Cu(II) analysis. Cobalt(II)-EDTA-BSA was the coating antigen in a heterologous indirect competitive ELISA (hicELISA), whereas Co(II)-EDTA-BSA-horseradish peroxidase (HRP) was the enzyme tracer in a heterologous direct competitive ELISA (hdcELISA). Both ELISAs were validated for detecting the content of Cu(II) in environmental waters. The ELISA data agreed well with those from graphite furnace atomic absorption spectroscopy. The methods of dev... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139476 Fri, 19 Aug 2011 12:06:34 +0100 5139476 http://www.medworm.com/index.php?rid=5139475&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819867%26dopt%3DAbstract Authors: Li H, Sun X Abstract In this paper, we report on the use of 3,4,9,10-perylenetetracarboxylic diimide microfibers (PDIMs) as an effective fluorescent sensing platform for DNA detection for the first time. This sensing system exhibits a detection limit as low as 15nmolL(-1) and has a high selectivity down to single-base mismatch. The general concept used in this approach is based on adsorption of fluorescently labeled single-stranded DNA (ssDNA) probe by PDIM due to the strong π-π stacking between unpaired DNA bases and PDIM. As a result, the fluorophore is brought into close proximity of PDIM, leading to substantial fluorescence quenching. In the presence of the target, the specific hybridization of the probe with its complementary DNA sequence generates a double stranded... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139475 Fri, 19 Aug 2011 12:06:28 +0100 5139475 http://www.medworm.com/index.php?rid=5139474&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819868%26dopt%3DAbstract In this report, we developed a universal assay method for both genomic DNA and proteins by using enzyme-based multi-component optical nanoprobes. The nanoprobes are gold nanoparticles assembled with bio-recognizing and signaling elements. We firstly demonstrated that the nanoprobes could detect unpurified asymmetric polymerase chain reaction (PCR) product from genomic DNA of Escherichia coli, with the sensitivity approximately 10 times higher than that of quantitative real-time PCR assay. The limit of detection (LOD) of our nanoprobe-based method is less than 10pg template DNA (target DNA). Using DNA aptamers as recognition elements, we also showed that as few as 0.1nM thrombin could be colorimetrically detected with high specificity. These results indicated that the enzyme-based multi-com... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139474 Fri, 19 Aug 2011 12:06:23 +0100 5139474 http://www.medworm.com/index.php?rid=5139473&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819869%26dopt%3DAbstract Authors: Tang H, Hiemstra S, Thompson JE Abstract An approach to sample and analyze single aerosolized droplets (<10nL) of solutions containing fluorescein isothiocyanate (FITC) labeled glycine (GLY) and glutamic acid (GLU) is demonstrated. The sampling approach is based on inertial impaction in which the sample particle is accelerated through a nozzle and directly into a small drop of buffered solution (20mM borate, pH=10) suspended at the end of a coaxial tube of stainless steel and a fused silica capillary. A spherical light scattering cell and laser (λ=532nm) is used to detect the arrival of particles at the buffered droplet. Upon dissolution and/or mixing, a portion of the sample is injected onto the fused silica capillary for subsequent chemical analysis by capillary elec... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139473 Fri, 19 Aug 2011 12:06:18 +0100 5139473 http://www.medworm.com/index.php?rid=5139472&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819870%26dopt%3DAbstract Authors: Li J, Dong F, Xu J, Liu X, Li Y, Shan W, Zheng Y Abstract A rapid and effective method for enantioselective determination of simeconazole enantiomers in food products (cucumber, tomato, apple, pear, wheat and rice) has been developed. The enantiomers were resolved by capillary gas chromatography (GC) using a commercial chiral column (BGB-172) and a temperature program from 150°C (held for 1min) and then raised at 10°Cmin(-1) to 240°C (held for 10min). This enantioselective gas chromatographic separation was combined with a clean-up/enrichment procedure based on the modification of QuEChERS (quick, easy, cheap, effective, rugged and safe) method. Co-extractives were removed with graphitized carbon black/primary secondary amine (GCB/PSA) solid-phase extraction (SPE) cartr... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139472 Fri, 19 Aug 2011 12:06:14 +0100 5139472 http://www.medworm.com/index.php?rid=5139471&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819871%26dopt%3DAbstract Authors: Shaaban H, Górecki T Abstract A high efficiency HPLC method was developed by coupling three sub-2μm columns in series and operating them at high temperature for the separation of selected non-steroidal anti-inflammatory drugs and veterinary antibiotics in environmental samples. The separation was performed at 80°C to reduce the solvent viscosity, thus reducing the column backpressure. The chromatographic performance of high temperature-extended column length HPLC method was used to determine the most widely used non-steroidal anti-inflammatory drugs and veterinary antibiotics such as sulphonamides in wastewater samples. The method could simultaneously determine 24 pharmaceuticals in short analysis time with high efficiency. The method involved pre-concentration and clea... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139471 Fri, 19 Aug 2011 12:06:10 +0100 5139471 http://www.medworm.com/index.php?rid=5139470&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819872%26dopt%3DAbstract Comment on "Application of a superoxide (O(2)(-)) thermal source (SOTS-1) for the determination and calibration of O(2)(-) fluxes in seawater" by Heller and Croot. Anal Chim Acta. 2011 Sep 19;702(1):144-5 Authors: Rose AL, Miller CJ, Fujii M, Waite TD PMID: 21819872 [PubMed - in process] (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139470 Fri, 19 Aug 2011 12:06:06 +0100 5139470 http://www.medworm.com/index.php?rid=5139469&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21819873%26dopt%3DAbstract Reply to comment on "Application of a superoxide (O(2)(-)) thermal sources (SOTS-1) for the determination and calibration of O(2)(-) fluxes in seawater". Anal Chim Acta. 2011 Sep 19;702(1):146-7 Authors: Heller MI, Croot PL PMID: 21819873 [PubMed - in process] (Source: Analytica Chimica Acta) Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139469 Fri, 19 Aug 2011 12:06:02 +0100 5139469 http://www.medworm.com/index.php?rid=5139468&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21839192%26dopt%3DAbstract Authors: Zheng J, Sugrue RJ, Tang K Abstract In terms of proteomic research in the 21st century, the realm of virology is still regarded as an enormous challenge mainly brought by three aspects, namely, studying on the complex proteome of the virus with unexpected variations, developing more accurate analytical techniques as well as understanding viral pathogenesis and virus-host interaction dynamics. Progresses in these areas will be helpful to vaccine design and antiviral drugs discovery. Mass spectrometry based proteomics have shown exceptional display of capabilities, not only precisely identifying viral and cellular proteins that are functionally, structurally, and dynamically changed upon virus infection, but also enabling us to detect important pathway proteins. In addition,... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139468 Fri, 19 Aug 2011 12:05:57 +0100 5139468 http://www.medworm.com/index.php?rid=5139467&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21839193%26dopt%3DAbstract Authors: Rozet E, Rudaz S, Marini RD, Ziémons E, Boulanger B, Hubert P Abstract Evaluation of analytical results reliability is of core importance as crucial decisions are taken with them. From the various methodologies to evaluate the fitness of purpose of analytical methods, overall measurement uncertainty estimation is more and more applied. Overall measurement uncertainty allows to combine simultaneously the remaining systematic influences to the random sources of uncertainty and allows assessing the reliability of results generated by analytical methods. However there are various interpretations on how to estimate overall measurement uncertainty, and thus various models for estimating it. Each model together with its assumptions has great impacts on the risks to abusively dec... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139467 Fri, 19 Aug 2011 12:05:53 +0100 5139467 http://www.medworm.com/index.php?rid=5139466&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21839194%26dopt%3DAbstract Authors: Perera PN, Schmidt M, Schuck PJ, Adams PD Abstract A new image analysis strategy is introduced to determine the composition and the structural characteristics of plant cell walls by combining Raman microspectroscopy and unsupervised data mining methods. The proposed method consists of three main steps: spectral preprocessing, spatial clustering of the image and finally estimation of spectral profiles of pure components and their weights. Point spectra of Raman maps of cell walls were preprocessed to remove noise and fluorescence contributions and compressed with PCA. Processed spectra were then subjected to k-means clustering to identify spatial segregations in the images. Cell wall images were reconstructed with cluster identities and each cluster was represented by the a... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139466 Fri, 19 Aug 2011 12:05:46 +0100 5139466 http://www.medworm.com/index.php?rid=5139465&cid=s_34388_59_f&fid=34388&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21839195%26dopt%3DAbstract Authors: Rodrigues JA, Barros AS, Carvalho B, Brandão T, Gil AM Abstract This paper describes the use of nuclear magnetic resonance (NMR) spectroscopy, in tandem with multivariate analysis (MVA), for monitoring the chemical changes occurring in a lager beer exposed to forced aging (at 45°C for up to 18 days). To evaluate the resulting compositional variations, both principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were applied to the NMR spectra of beer recorded as a function of aging and a clear aging trend was observed. Inspection of PLS-DA loadings and peak integration enabled the changing compounds to be identified, revealing the importance of well known markers such as 5-hydroxymethylfurfural (5-HMF) as well as a range of other relev... Analytica Chimica Acta journals http://www.medworm.com/rss/comments.php?id=5139465 Fri, 19 Aug 2011 12:05:38 +0100 5139465