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Recent developments in homogeneous and dispersive liquid-liquid extraction for inorganic elements determination. A review.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This review aims to provide an overview of homogeneous liquid-liquid extraction (HLLE) and dispersive liquid-liquid microextraction (DLLME) methods and their potential use in inorganic analysis. Relevant applications to the determination of metal ions, metalloids and organometals are included. The phase separation mechanisms of these unconventional solvent extraction techniques are discussed. The new trends in the field of miniaturization and automation are presented, while proposing future trends and potential new areas for their application. PMID: 19836497 [PubMed - in process] (Source: Talanta)
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Anthemidis AN, Ioannou KI Tags: Talanta Source Type: journals

Effect of variation in argon content of calibration gases on determination of atmospheric carbon dioxide.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Carbon dioxide (CO(2)) is a greenhouse gas that makes by far the largest contribution to the global warming of the Earth's atmosphere. For the measurements of atmospheric CO(2) a non-dispersive infrared analyzer (NDIR) and gas chromatography are conventionally being used. We explored whether and to what degree argon content can influence the determination of atmospheric CO(2) using the comparison of CO(2) concentrations between the sample gas mixtures with varying Ar amounts at 0 and 18.6mmolmol(-1) and the calibration gas mixtures with Ar at 8.4, 9.1, and 9.3mmolmol(-1). We newly discovered that variation of Ar conten...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Min D, Kang N, Moon DM, Lee JB, Lee DS, Kim JS Tags: Talanta Source Type: journals

Biomonitoring of metal contamination in a marine prosobranch snail (Nassarius reticulatus) by imaging laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
An imaging mass spectrometric method using laser ablation inductively coupled plasma spectrometry (LA-ICP-MS) was developed to determine Cu, Zn, Cd, Hg and Pb and metal distribution in longitudinal tissue sections of the marine snail Nassarius reticulatus (Gastropoda, Prosobranchia). Snails were sampled in northern Brittany (France) at three stations with different contamination levels. The quantification of metal distribution (imaging or mapping) in a thin slice of the snail tissue was carried out using different strategies: by one-point calibration and via matrix-matched laboratory standards using different biologica...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Santos MC, Wagner M, Wu B, Scheider J, Oehlmann J, Cadore S, Becker JS Tags: Talanta Source Type: journals

Ultrasound energy focused in a glass probe: An approach to the simultaneous and fast extraction of trace elements from sediments.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The 3051 USEPA method (or alternatively, the 3051A) can be considered nowadays as a reference method to extract metals from sediments. However, after microwave heating, the sample must be allowed to cool down, which results in a considerable lengthening of the whole analytical process. Microwave ovens and their maintenance are, in addition, expensive, and its use is relatively dangerous. The use of ultrasound focused energy to assist the extraction of chemicals from solid samples is a safe and relatively cheap technique. In this work we propose a new method to extract simultaneously several elements from sediments usin...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: de Vallejuelo SF, Barrena A, Arana G, de Diego A, Madariaga JM Tags: Talanta Source Type: journals

Determination of soil amino acids by high performance liquid chromatography-electro spray ionization-mass spectrometry derivatized with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Determination of amino acids by mass spectrometry (MS) is an important technique to investigate soil nitrogen transformation and cycling as amino acids being the major nitrogen-containing compounds in soil organic matter. However, researchers have long faced a critical problem in coupling an efficient separation technique to a sensitive MS detection system simultaneously. In this context, we established a new method of liquid chromatography coupled to mass spectrometry based on the 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) derivatization method for convenient and accurate quantification of amino acids in so...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Hou S, He H, Zhang W, Xie H, Zhang X Tags: Talanta Source Type: journals

Sensitive determination of verticine and verticinone in Bulbus Fritillariae by ionic liquid assisted capillary electrophoresis-electrochemiluminescence system.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
CE/Ru(bpy)(3)(2+) electrochemiluminescence (ECL) system with the assistance of ionic liquids (ILs) was successfully established for sensitive determination of verticine and verticinone in Bulbus Fritillariae for the first time. Migration behavior of alkaloid largely relies on the hydrogen bonding interactions between alkyl imidazolium cations in ILs and the alkaloids. Running buffer containing 40mmol/L 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF(4)) IL-8mmol/L phosphate resulted in significant changes in separation selectivity for alkaloids with similar structures. The highest sensitivity of the detection was...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Gao Y, Xu Y, Han B, Li J, Xiang Q Tags: Talanta Source Type: journals

Biotin induced fluorescence enhancement in resonance energy transfer and application for bioassay.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A novel method to significantly enhance fluorescence resonance energy transfer (FRET) signal which occurred from fluoresceine isothiocyanate (FITC) to Dylight 549 was studied in this paper. Streptavidin was labeled with the donor fluorophore FITC and biotinamide was conjugated to the acceptor Dylight 549. When biotinamide bound to streptavidin, FRET would occur from FITC to Dylight 549 while a remarkable fluorescence enhancement of streptavidin-FITC was observed. The fluorescence enhancement of streptavidin-FITC in the presence of biotin was utilized in the FRET system to obtain higher fluorescence signal. Increase of ...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Hu S, Yang H, Cai R, Liu Z, Yang X Tags: Talanta Source Type: journals

Peroxidase activity-structure relationship of the intermolecular four-stranded G-quadruplex-hemin complexes and their application in Hg(2+) ion detection.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The peroxidase activities of the complexes of hemin and intermolecular four-stranded G-quadruplexes formed by short-stranded X(n)G(m)X(p) sequences (X=A, T or C), especially T(n)G(m)T(p) sequences, were compared. The results, combining with those of circular dichroism (CD) spectra and acid-base transition study for DNA-hemin complexes, provide some important information about DNAzymes based on G-quadruplex-hemin complexes, such as the formation of a G-quadruplex structure is an important factor for determining whether a DNA sequence can enhance the catalytic activity of hemin; both intramolecular parallel G-quadruplexe...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Kong DM, Wu J, Wang N, Yang W, Shen HX Tags: Talanta Source Type: journals

Measurement uncertainty in analytical studies based on surface plasmon resonance.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The sensitivity of surface plasmon resonance (SPR) transducers depends on the thickness and spatial organization of interfacial structures at their surfaces. This is because the response of the SPR sensor is determined by integrating the distance-dependent refractive index (spatial interfacial architectures), weighted by the square of the electromagnetic field, from zero to infinite distance. The effect of SPR transducer sensitivity variation on the accuracy of SPR analysis is considered. Our quantitative estimation (based on the results of refractometric studies) gave a value for sensitivity variation of about 3% for ...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Boltovets PM, Snopok BA Tags: Talanta Source Type: journals

Nir-chemical imaging study of acetylsalicylic acid in commercial tablets.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Near Infrared Chemical Imaging (NIR-CI) is demonstrating an increasing interest in pharmaceutical research since it meets the challenging analytical needs of pharmaceutical quality and may serve as a versatile adjunct to conventional NIR spectroscopy in many fields. The direct analysis of samples by using hyperspectral imaging techniques, which provide a NIR spectrum in each pixel of the image, generates a big amount of information from one sample. Focusing the interest in pharmaceutical research, several chemometric algorithms are demonstrating their usefulness extracting the relevant information (i.e. quantitative de...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Cruz J, Bautista M, Amigo JM, Blanco M Tags: Talanta Source Type: journals

One step to detect the latent fingermarks with gold nanoparticles.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A simple and environment friendly chemical route for detecting latent fingermarks by one-step single-metal nanoparticles deposition method (SND) was achieved successfully on several non-porous items. Gold nanoparticles (AuNPs) synthesized using sodium borohydride as reducing agent in the presence of glucose, were used as working solution for latent fingermarks detection. The SND technique just needs one step to obtain clear ridge details in a wide pH range (2.5-5.0), whereas the standard multi-metal deposition (MMD) technique requires six baths in a narrow pH range (2.5-2.8). The SND is very convenient to detect latent...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Gao D, Li F, Song J, Xu X, Zhang Q, Niu L Tags: Talanta Source Type: journals

Electrochemical determination of melamine using oligonucleotides modified gold electrodes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A novel and simple electrochemical method for determination of melamine is developed based on oligonucleotides film modified gold electrodes. The electrochemical probe of ferricyanide was used to investigate the interactions between oligonucleotides and melamine. Results of cyclic voltammetries, differential pulse stripping voltammetries, electrochemical impedance spectrometry and atomic force microscope, proved that melamine might interact with oligonucleotides mainly through electrostatic and hydrogen-bonding interactions. The interactions between oligonucleotides and melamine lead to the increase in the peak current...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Cao Q, Zhao H, Zeng L, Wang J, Wang R, Qiu X, He Y Tags: Talanta Source Type: journals

Determination of oleic acid in sunflower seeds by infrared spectroscopy and multivariate calibration method.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A method for the determination of oleic acid in sunflower seeds is proposed. One hundred samples of sunflower seeds were analyzed by near-infrared diffuse reflectance spectroscopy (NIRDRS). The direct measures were realized in ground and sifted seeds. The PLS multivariate calibration model was obtained using first derivate absorbance values as response matrix, while the oleic acid concentration matrix was obtained analyzing the seed samples by gas chromatography with a flame ionization detector (GC-FID). The NIRDRS-PLS model was validated externally using unknown samples of sunflower seeds. The accuracy and precision o...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Cantarelli MA, Funes IG, Marchevsky EJ, Camiña JM Tags: Talanta Source Type: journals

Determination of phenylurea herbicides in aqueous samples using partitioned dispersive liquid-liquid microextraction.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Partitioned dispersive liquid-liquid microextraction (PDLLME), using THF as the dispersive solvent and dichloromethane as the extraction solvent, was utilized to isolate and concentrate phenylurea herbicides (PUHs) from aqueous samples. In PDLLME, a dispersive solvent should be able to partition in the organic extractant droplets to effectively extract the polar organic compounds from aqueous samples. The mixture of the water-immiscible extractant and the partitioned dispersive solvent was obtained by centrifugation, dried under low pressure, reconstituted in methanol-water mixture (1:1), and injected into a HPLC syste...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Chou TY, Lin SL, Fuh MR Tags: Talanta Source Type: journals

Online process control of acidic texturisation baths with ion chromatography.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Etching of silicon with mixtures of hydrofluoric acid and nitric acid is a widely used process in silicon solar cell fabrication. One precondition for an optimized usage of the acidic etching baths is the exact knowledge of the chemical bath composition. In this paper, we investigated a fast and online-capable method for the total analysis of all bath constituents by ion chromatography. The chromatographical system consists of a low-volume injection valve, which injects the concentrated samples directly into the KOH-based eluent. After separation and detection of nitrate and fluoride, a post-column derivatization with ...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Zimmer M, Oltersdorf A, Rentsch J Tags: Talanta Source Type: journals

Development of a methodology for the simultaneous determination of inorganic and organolead compounds using supercritical fluid extraction followed by gas chromatography-mass spectrometry and its application to environmental matrices.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A method for the extraction of triethyl lead (TEL(+)), trimethyl lead (TML(+)), and Pb(2+) from sand was developed using supercritical modified CO(2)-CH(3)OH extraction and in situ complexation with sodium diethyldithiocarbamate (NaDDTC) using a 2(5) factorial exploratory design is described. The screened variables were (i) pressure (69-193bar), (ii) temperature (40-150 degrees C), (iii) ligand amount (0-100mg), (iv) methanol volume (0.0-0.5mL) and (v) static time (0-45min). The optimum extraction conditions found were as follow: pressure, 193bar; temperature, 40 degrees C; amount of NaDDTC, 100mg; methanol volume, 0.5...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Zúñiga MC, Jover E, Arancibia V, Bayona JM Tags: Talanta Source Type: journals

Smart electrochemical sensor for some neurotransmitters using imprinted sol-gel films.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A hybrid sol-gel material formed by acid hydrolysis of a mixture of tetraethylorthosilicate (TEOS) and phenyltriethylorthosilicate (PTEOS) as functional monomers was imprinted by tyramine and dopamine as template molecules for the purpose of molecular recognition. Imprinted materials were spin coated as thin films on the surface of glassy carbon electrodes and then were characterized using cyclic voltammetry (CV). After extraction of the encapsulated molecules, imprinted films were tested in solutions of their templates and other molecules. Rebinding experiments were followed by electrochemical characterization using s...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Atta NF, Abdel-Mageed AM Tags: Talanta Source Type: journals

Voltammetric performance and application of a sensor for sodium ions constructed with layered birnessite-type manganese oxide.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The preparation and electrochemical characterization of a carbon paste electrode modified with layered birnessite-type manganese oxide for use as a sodium sensor is described. The effects of powder synthesis process (sol-gel and redox precipitation) for birnessite on the electrochemical activity of the sensor was investigated by cyclic voltammetry. The carbon paste electrode modified with birnessite-type manganese oxide that was synthesized by the sol-gel method showed a best electrochemical for sodium ions. The detection is based on the measurement of anodic current generated by oxidation of Mn(III) to Mn(IV) at the s...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Martinez MT, Lima AS, Bocchi N, Teixeira MF Tags: Talanta Source Type: journals

Salt-assisted liquid-liquid microextraction with water-miscible organic solvents for the determination of carbonyl compounds by high-performance liquid chromatography.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A simple and rapid method has been reported for the determination of carbonyl compounds involving reaction with 2,4-dinitrophenylhydrazine and extraction of hydrazones with water-miscible organic solvent acetonitrile when the phase separation occurs by addition of ammonium sulphate, a process called salt-assisted liquid-liquid microextraction. The extract was analyzed by high-performance liquid chromatography with UV detection at 360nm. The procedure has been optimized with respect to solvent suitable for extraction, salt for phase separation between water and organic solvent, reaction temperature and reaction time. Th...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Gupta M, Jain A, Verma KK Tags: Talanta Source Type: journals

An efficient thiourea-based colorimetric chemosensor for naked-eye recognition of fluoride and acetate anions: UV-vis and (1)HNMR studies.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
An efficient colorimetric chemosensor with a thiourea binding site and 2-amino-6-nitrobenothiazole as a signaling unit has been synthesized by dithiocarbamate approach. The chemosensor has been utilized for selective recognition of fluoride and acetate anions in dry DMSO solution by UV-vis and (1)H NMR titration experiments. The chemosensor has shown naked-eye sensitivity for both the anions in solution. PMID: 19836516 [PubMed - in process] (Source: Talanta)
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Misra A, Shahid M, Dwivedi P Tags: Talanta Source Type: journals

A simple method for fabrication of sole composition nickel hexacyanoferrate modified electrode and its application.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Nickel hexacyanoferrate film modified gold electrode was prepared by a simple chemical deposition procedure from a fresh prepared solution containing ferricyanide, Ni(2+), and sodium nitrate. The resultant films have solo composition and are significantly stable as compared to the electrochemically deposited NiHCF films. For different concentrations of Na(+) in the solution, the formal potential values of NiHCF shift according to the Nernstian behavior with a slope of 48mV in the range of 10(-4) to 1.0M. The NiHCF film was also used for the electrocatalytic oxidation of ascorbic acid. The anodic peak current observed i...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Chen W, Tang J, Cheng HJ, Xia XH Tags: Talanta Source Type: journals

Borate complexation-assisted field-enhanced sample injection for on-line preconcentration of cis-diol-containing compounds in capillary electrophoresis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A new on-line preconcentration technique called borate complexation-assisted field-enhanced sample injection (BCA-FESI) was proposed for preconcentrating cis-diol-containing compounds (CDCCs) in capillary electrophoresis (CE). The principle relies on amplification of the difference in the electrophoretic mobilities of CDCC in sample matrix and background electrolyte (BGE) through complexation of CDCC with borate in a sample matrix of basic pH and dissociation of the complex in a BGE of acidic pH. Meanwhile, CDCC and borate ions electro-injected into the capillary are finally in neutral state, which maintains the pre-fi...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Liu J, Zhu F, Liu Z Tags: Talanta Source Type: journals

Dielectrophoresis assisted immuno-capture and detection of foodborne pathogenic bacteria in biochips.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study integrated dielectrophoresis (DEP) with non-flow through biochips to enhance the immuno-capture and detection of foodborne pathogenic bacteria. It demonstrated two major functions provided by DEP to improve the chip performance: (i) concentrating bacterial cells from the suspension to different locations on the chip surface by positive and negative DEP; (ii) making the cells in close contact with the immobilized antibodies on the chip surface so that immuno-capture efficiency can be dramatically enhanced. The microchip achieved the immuno-capture efficiencies of approximately 56.0% and approximately 64.0% to Sal...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Yang L Tags: Talanta Source Type: journals

Statistical mixture design development of digestion methods for Oyster tissue using inductively coupled plasma optical emission spectrometry for the determination of metallic ions.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The quantitative determination of chemical elements in organic or biological samples is an important analytical problem. Normally the elements to be determined in the organic matrix must be transformed into a simple inorganic form. A digestion method by heating on a block digestor has been developed for the determination of Al, As, Ba, Ca, Cd, Co, Cu, Fe, Mg, Mn, V and Zn in Oyster tissue by ICP OES. A simplex centroid statistical mixture design has been used to study the effects of changing HNO(3), HCl and H(2)O(2) reagent proportions on the digestion of these samples. Response surface and principal component analyses...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Nano RM, Bruns RE, Ferreira SL, Baccan N, Cadore S Tags: Talanta Source Type: journals

Exploring fiber optic approach to sense humid environment over nano-crystalline zinc oxide film.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A novel humidity sensor made up of nano-crystalline zinc oxide (ZnO) film, coated onto the U-shaped typical glass substrate as a wave guide, conjugated with an optical fiber and He-Ne un-polarized laser source. The nano-crystalline zinc oxide (ZnO) was synthesized using single molecular precursor method. The resulting material was characterized with Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), thermogravimetric-differential thermal analysis (TG-DTA) and scanning electron microscopy (SEM). In the thin film, ZnO particles exhibited the wurtzite phase structure with the particle size in a di...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Shukla SK, Tiwari A, Parashar GK, Mishra AP, Dubey GC Tags: Talanta Source Type: journals

An approach to identifying sequential metabolites of a typical phenylethanoid glycoside, echinacoside, based on liquid chromatography-ion trap-time of flight mass spectrometry analysis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study proposed a novel approach for rapidly identifying the complicated and unpredictable metabolites of ECH, based on the powerful liquid chromatography hybrid ion trap and time of flight mass spectrometry (LC/MS-IT-TOF) analysis. Four degradation products were rapidly identified via the "fragmentation-degradation" comparisons. Five phase I and phase II metabolites of the degradation products were rapidly characterized via the crossover mass differences comparisons of their quasi-molecular ions with the potential precursors. Four direct phase I and phase II metabolites of the parent compound were identified by the ma...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Wang Y, Hao H, Wang G, Tu P, Jiang Y, Liang Y, Dai L, Yang H, Lai L, Zheng C, Wang Q, Cui N, Liu Y Tags: Talanta Source Type: journals

A renewable copper electrode as an amperometric flow detector for nitrate determination in mineral water and soft drink samples.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A novel approach was developed for nitrate analysis in a FIA configuration with amperometric detection (E=-0.48V). Sensitive and reproducible current measurements were achieved by using a copper electrode activated with a controlled potential protocol. The response of the FIA amperometric method was linear over the range from 0.1 to 2.5mmolL(-1) nitrate with a detection limit of 4.2mumolL(-1) (S/N=3). The repeatability of measurements was determined as 4.7% (n=9) at the best conditions (flow rate: 3.0mLmin(-1), sample volume: 150muL and nitrate concentration: 0.5mmolL(-1)) with a sampling rate of 60samplesh(-1). The me...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Gamboa JC, Peña RC, Paixão TR, Bertotti M Tags: Talanta Source Type: journals

A single-wall carbon nanotubes modified edge plane pyrolytic graphite sensor for determination of methylprednisolone in biological fluids.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
An electrochemical protocol based on reduction is developed to determine methylprednisolone using single-wall carbon nanotubes (SWNTs) modified edge plane pyrolytic graphite electrode (EPPGE). To obtain a good sensitivity, instrumental variables were studied using Square Wave Voltammetry (SWV). The voltammetric results indicate that SWNTs modified EPPGE remarkably enhances the reduction of methylprednisolone which leads to considerable improvement of peak current with shift of peak potential to less negative values. The voltammetric current showed a linear response for methylprednisolone concentration in the range 5-50...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Goyal RN, Chatterjee S, Rana AR Tags: Talanta Source Type: journals

Prion protein detection in serum using micromechanical resonator arrays.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we have continued development of a micromechanical resonator array that is capable of detecting PrP(c) in bovine blood serum. The sensitivity of the resonators for the detection of PrP(c) is further enhanced by the use of secondary mass labels. A pair of antibodies is used in a sandwich immunoassay format to immobilize PrP(c) on the surface of resonators and attach nanoparticles as secondary mass labels to PrP(c). Secondary mass labeling is optimized in terms of incubation time to maximize the frequency shifts that correspond to the presence of PrP(c) on the surface of resonators. Our results show that a min...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Varshney M, Waggoner PS, Montagna RA, Craighead HG Tags: Talanta Source Type: journals

Main fatty acid classes in vegetable oils by SB-ATR-Fourier transform infrared (FTIR) spectroscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The prospect of using single bounce attenuated total reflectance (SB-ATR)-Fourier transform infrared (FTIR) spectroscopy as a rapid quantitative tool to determine the main fatty acid groups present in different edible oils was investigated. Partial least squares (PLS) calibrations were developed using SB-ATR-FTIR spectra which were associated with fatty acid groups (saturated, trans, mono- and polyunsaturated) using quantitative data obtained by gas chromatography (GC). Good calibrations were obtained for all main four fat groups (saturated, mono, trans and polyunsaturated) with excellent precision. The coefficient of ...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Sherazi ST, Talpur MY, Mahesar SA, Kandhro AA, Arain S Tags: Talanta Source Type: journals

Triphenylmethane dyes as fluorescent probes for G-quadruplex recognition.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Triphenylmethane (TPM) dyes normally render rather weak fluorescence due to easy vibrational deexcitation. However, when they stack onto the two external G-quartets of a G-quadruplex (especially intramolecular G-quadruplex), such vibrations will be restricted, resulting in greatly enhanced fluorescence intensities. Thus, TPM dyes may be developed as sensitive G-quadruplex fluorescent probes. Here, fluorescence spectra and energy transfer spectra of five TPM dyes in the presence of G-quadruplexes, single- or double-stranded DNAs were compared. The results show that the fluorescence spectra of four TPM dyes can be used t...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Guo JH, Zhu LN, Kong DM, Shen HX Tags: Talanta Source Type: journals

Theoretical and experimental methods of determination of the breakthrough volume of SPE sorbents.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Solid-phase extraction is one of the most popular sample preparation methods. The selection of the appropriate extraction system is an important stage in the elaboration of analytical procedure. In this case, the knowledge of the interactions between isolated compounds, sorbent and elution solvents seems to be important. The extraction ability of sorbents in the SPE bed depends also on: (i) the bed capacity; (ii) the volume of sample loaded, (iii) the nature and volumes of conditioning solvents and eluents. One of the important parameters is the breakthrough volume, which determines the maximum volume of water sample w...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Bielicka-Daszkiewicz K, Voelkel A Tags: Talanta Source Type: journals

Potentialities of two solventless extraction approaches-Stir bar sorptive extraction and headspace solid-phase microextraction for determination of higher alcohol acetates, isoamyl esters and ethyl esters in wines.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A stir bar sorptive extraction with liquid desorption followed by large volume injection coupled to gas chromatography-quadrupole mass spectrometry (SBSE-LD/LVI-GC-qMS) was evaluated for the simultaneous determination of higher alcohol acetates (HAA), isoamyl esters (IsoE) and ethyl esters (EE) of fatty acids. The method performance was assessed and compared with other solventless technique, the solid-phase microextraction (SPME) in headspace mode (HS). For both techniques, influential experimental parameters were optimised to provide sensitive and robust methods. The SBSE-LD/LVI methodology was previously optimised in...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Perestrelo R, Nogueira JM, Câmara JS Tags: Talanta Source Type: journals

Modification of carbon screen-printed electrodes by adsorption of chemically synthesized Bi nanoparticles for the voltammetric stripping detection of Zn(II), Cd(II) and Pb(II).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A simple procedure for the chemical synthesis of bismuth nanoparticles and subsequent adsorption on commercial screen-printed carbon electrodes offer reliable quantitation of trace zinc, cadmium and lead by anodic stripping square-wave voltammetry in nondeareated water samples. The influence of two hydrodynamic configurations (convective cell and flow cell) and the effect of various experimental variables upon the stripping signals at the bismuth-coated sensor are explored. The square-wave peak current signal is linear over the low ngmL(-1) range (120s deposition), with detections limits ranging from 0.9 to 4.9ngmL(-1)...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Rico MA, Olivares-Marín M, Gil EP Tags: Talanta Source Type: journals

Optimization of clean-up procedure for patulin determination in apple juice and apple purees by liquid chromatography.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Patulin (PAT) is a mycotoxin produced in fruits, mainly in apples, by several fungal species that can be carried into industrial apple juice by-products during factory processing. An analytical method for determination of PAT in apple juice and another one for determination of this compound in apple purees and apple compotes by liquid chromatography are proposed in the present paper. These methods have better precision and sensitivity than previously reported methods and focus mainly on extraction and clean-up. To accomplish analytical methods with higher accuracy, lower limits of detection and simpler procedures for a...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Valle-Algarra FM, Mateo EM, Gimeno-Adelantado JV, Mateo-Castro R, Jiménez M Tags: Talanta Source Type: journals

Optimisation and validation of programmed temperature vaporization (PTV) injection in solvent vent mode for the analysis of the 15+1 EU-priority PAHs by GC-MS.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This paper presents the optimisation of a programmed temperature vaporization solvent vent (PTV-SV) injection gas chromatographic mass spectrometric (GC-MS) method for the analysis of the 15+1 EU-priority PAHs in food extracts. Three operation parameters (vent time, vent flow and vent pressure) were optimised by applying a D-optimal experimental design. Among these variables, vent time showed the highest effect on the analytical response (signal intensity) of the target PAHs. The 15+1 EU-priority PAHs were analysed in solvent solutions and in extracts of fortified sausage. In addition, blank lamb meat extracts were pre...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Gómez-Ruiz JA, Cordeiro F, López P, Wenzl T Tags: Talanta Source Type: journals

Isolation of novel indole-3-acetic acid conjugates by immunoaffinity extraction.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
An analytical protocol for the isolation and quantification of indole-3-acetic acid (IAA) and its amino acid conjugates was developed. IAA is an important phytohormone and formation of its conjugates plays a crucial role in regulating IAA levels in plants. The developed protocol combines a highly specific immunoaffinity extraction with a sensitive and selective LC-MS/MS analysis. By using internal standards for each of the studied compounds, IAA and seven amino acid conjugates were analyzed in quantities of fresh plant material as low as 30mg. In seeds of Helleborus niger, physiological levels of these compounds were f...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Pencík A, Rolcík J, Novák O, Magnus V, Barták P, Buchtík R, Salopek-Sondi B, Strnad M Tags: Talanta Source Type: journals

Differential pulse voltammetric simultaneous determination of noradrenalin and acetaminophen using a hematoxylin biosensor.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A highly efficient noradrenalin (NA) biosensor was fabricated on the basis of hematoxylin electrodeposited on a glassy carbon electrode, GCE. The cyclic voltammetric responses of the hematoxylin biosensor at various scan rates, which were obtained in a 0.25mmolL(-1) NA solution, showed the characteristic shape typical of an EC(cat) process. The kinetic parameters such as electron transfer coefficient, alpha, the catalytic electron transfer rate constant, k', and the standard catalytic electron transfer rate constant, k(0), for oxidation of NA at the hematoxylin biosensor surface were estimated using cyclic and RDE volt...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Nasirizadeh N, Zare HR Tags: Talanta Source Type: journals

Solid phase extraction-spectrophotometric determination of fluoride in water samples using magnetic iron oxide nanoparticles.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A new, sensitive, fast and simple method using magnetic iron oxide nanoparticles (MIONs), as an adsorbent has been developed for extraction, preconcentration and determination of traces of fluoride ions. The determination method is based on the discoloration of Fe(III)-SCN complex with extracted fluoride ions which was subsequently monitored spectrophotometrically at lambda(max)=458nm. Various parameters affecting the adsorption of fluoride by the MIONs have been investigated, such as pH of the solution, type, volume and concentration of desorbing reagent, amount of adsorbent and interference effects. A linear response...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Parham H, Rahbar N Tags: Talanta Source Type: journals

A centrifugal microanalysis system for the determination of nitrite and hexavalent chromium.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A centrifugal microanalysis system using spectrophotometric detection has been developed for the determination of nitrite and chromium VI. The system was designed to illustrate the potential of centrifugal microfluidic systems for on-site (field) analysis of waters. The performance was significantly better than manual/visual field test systems and approaches that of bench top systems with detection limits of 0.008mgL(-1) NO(2)(-)-N and 0.03mgL(-1) Cr(6+). The system used pre-loaded solid reagents on the disc, providing ease of use, and could process up to 24 samples simultaneously. Precision was enhanced by the use of ...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Lacroix-Fralish A, Clare J, Skinner CD, Salin ED Tags: Talanta Source Type: journals

Measurement of total Zn and Zn isotope ratios by quadrupole ICP-MS for evaluation of Zn uptake in gills of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study evaluates the potential use of stable zinc isotopes in toxicity studies measuring zinc uptake by the gills of brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss). The use of stable isotopes in such studies has several advantages over the use of radioisotopes, including cost, ease of handling, elimination of permit requirements, and waste disposal. A pilot study using brown trout was performed to evaluate sample preparation methods and the ability of a quadrupole inductively coupled plasma mass spectrometer (ICP-MS) system to successfully measure changes in the (67)Zn/(66)Zn ratios for planned expo...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Wolf RE, Todd AS, Brinkman S, Lamothe PJ, Smith KS, Ranville JF Tags: Talanta Source Type: journals

Determination of cobalt ions at nano-level based on newly synthesized pendant armed macrocycle by polymeric membrane and coated graphite electrode.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Poly(vinylchloride) (PVC) based membranes of macrocycles 2,3,4:9,10,11-dipyridine-1,3,5,8,10,12-hexaazacyclotetradeca-2,9-diene (L(1)) and 2,3,4:9,10,11-dipyridine-1,5,8,12-tetramethylacrylate-1,3,5,8,10,12-hexaazacyclotetradeca-2,9-diene (L(2)) with NaTPB and KTpClPB as anion excluders and dibutylphthalate (DBP), benzyl acetate (BA), dioctylphthalate (DOP), o-nitrophenyloctyl ether (o-NPOE) and tri-n-butylphosphate (TBP) as plasticizing solvent mediators were prepared and investigated as Co(2+) selective electrodes. The best performance was observed with the membranes having the composition L(2):PVC:TBP:NaTPB in the r...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Singh AK, Singh P, Bhattacharjee G Tags: Talanta Source Type: journals

Quercetin molecularly imprinted polymers: Preparation, recognition characteristics and properties as sorbent for solid-phase extraction.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Molecular imprinted polymers (MIPs) were prepared through thermal polymerization by using quercetin as the template molecule, acrylamide (AA) as the functional monomer and ethylene glycol dimethacrylate (EDMA) as the cross-linker in the porogen of tetrahydrofuran (THF). The synthesized MIPs were identified by both Fourier transform infrared (FTIR) and scanning electron microscope (SEM). Systematic investigations of the influences of key synthetic conditions, including functional monomers, porogens and cross-linkers, on the recognition properties of the MIPs were conducted. Scatchard analysis revealed that the homogeneo...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Song X, Li J, Wang J, Chen L Tags: Talanta Source Type: journals

Improved selection of LMW over HMW proteins from human plasma by mesoporous silica particles with external modification.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we present, to our knowledge, the first demonstration of alkyl-diol@SiO(2) mesoporous material MCM-41 (alkyl-diol group on the external surface of mesoporous material) for selective extraction of LMW proteins and peptides from complex biological samples. The adsorption kinetics of LMW proteins, the influence of pH on adsorption and the desorption recovery by different elution solvents were investigated by using standard proteins as model samples. It was demonstrated that the modification of alkyl-diol group on the external surface could efficiently decrease the adsorption of HMW protein and increase the deso...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Qi Y, Wei J, Wang H, Zhang Y, Xu J, Qian X, Guan Y Tags: Talanta Source Type: journals

Coffee aroma-Statistical analysis of compositional data.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Solid-phase microextraction in headspace mode coupled with gas chromatography-mass spectrometry was applied to the determination of volatile compounds in 30 commercially available coffee samples. In order to differentiate and characterize Arabica and Robusta coffee, six major volatile compounds (acetic acid, 2-methylpyrazine, furfural, 2-furfuryl alcohol, 2,6-dimethylpyrazine, 5-methylfurfural) were chosen as the most relevant markers. Cluster analysis and principal component analysis (PCA) were applied to the raw chromatographic data and data processed by centred logratio transformation. PMID: 19836541 [PubMed - i...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Korhonová M, Hron K, Klimcíková D, Müller L, Bednár P, Barták P Tags: Talanta Source Type: journals

The problem of arsenic interference in the analysis of Cd to evaluate its extractability in soils contaminated by arsenic.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The arsenic (As) spectral interference observed in the determination of cadmium (Cd) by inductively coupled plasma atomic emission spectrometry (ICP-AES) was studied in atomic absorption spectrometry (AAS) using flame (FAAS) and graphite furnace (GFAAS) as atomizers. The soils of 15 kitchen gardens located near two smelters in the North of France were selected according the ratio As/Cd. Four different extracting solutions usually used to evaluate the mobility of Cd were chosen to extract Cd from these soil samples: citric acid 0.11M, acetic acid 0.11M, calcium chloride 0.01M and water. The quantitative determinations o...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Waterlot C, Douay F Tags: Talanta Source Type: journals

A new easy method for specific measurement of active myeloperoxidase in human biological fluids and tissue extracts.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The SIEFED ("Specific Immunological Extraction Followed by Enzymatic Detection") method already developed for the specific detection of the activity of equine myeloperoxidase (MPO) was adapted for the specific measurement of active human MPO in biological fluids or tissue extracts. The method consists of the extraction of MPO from aqueous solutions by immobilized anti-MPO antibodies followed by a washing (to eliminate the extraction medium and the biological fluid with their possible interfering molecules) and the measurement of the activity of MPO with a detection system containing a fluorogenic substrate, H(2)O(2) an...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Franck T, Kohnen S, Boudjeltia KZ, Van Antwerpen P, Bosseloir A, Niesten A, Gach O, Nys M, Deby-Dupont G, Serteyn D Tags: Talanta Source Type: journals

Optimization of FLEC((R))-SPME for field passive sampling of VOCs emitted from solid building materials.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The FLEC((R))-SPME sampler, described in a previous paper, consists of an emission cell coupled with solid phase microextraction (SPME) for passive sampling of VOCs emitted from building materials. It represents an interesting alternative to standard dynamic sampling protocol as it is easier to implement. If standard dynamic sampling determines emission rates, passive FLEC((R))-SPME aims to the determination of the concentration in air at the material surface. That could be assumed provided that material/air equilibrium is reached. Thus, VOCs emission kinetics were studied for 3 different materials (pine wood panel, ca...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Nicolle J, Desauziers V, Mocho P, Ramalho O Tags: Talanta Source Type: journals

Simple water analysis of golf link pesticides by means of batch-wise adsorption and supercritical fluid extraction.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Here, a simple new method is proposed to evaluate water for the presence of pesticides. Specifically, pesticides for golf link maintenance were used as the targets for this investigation. Water samples containing the pesticides were mixed with particulate adsorbent, after which the pesticides were extracted from the adsorbents using supercritical fluid carbon dioxide and then analyzed by gas chromatography-mass spectrometry. The recoveries of pesticides were examined with several types of adsorbents and found to be related to their octanol/water partition coefficients (K(ow)) for most of the adsorbents. Good recoveries...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Chikushi H, Hirota K, Yoshida N, Edamura T, Toda K Tags: Talanta Source Type: journals

Six orders of magnitude dynamic range in capillary electrophoresis with ultrasensitive laser-induced fluorescence detection.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
An ultrasensitive laser-induced fluorescence detector was used with capillary electrophoresis for the study of 5-carboxy-tetramethylrhodamine. The raw signal from the detector provided roughly three orders of magnitude dynamic range. The signal saturated at high analyte concentrations due to the dead time associated with the single-photon counting avalanche photodiode employed in the detector. The signal can be corrected for the detector dead time, providing an additional order of magnitude dynamic range. To further increase dynamic range, two fiber-optic beam-splitters were cascaded to generate a primary signal and tw...
Source: Talanta - October 21, 2009 Category: Chemistry Authors: Whitmore CD, Essaka D, Dovichi NJ Tags: Talanta Source Type: journals