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Zr and U determination at trace level in simulated deep groundwater by Q ICP-MS using extraction chromatography
18 January 2013,
09:51:33
15 March 2013
Publication year: 2013
Source:Talanta, Volume 106
In the framework of trace element analysis by Q ICP-MS in a simulated deep Callovo-Oxfordian groundwater, separation procedures based on extraction chromatography were developed to eliminate the high salt contents and to concentrate Zr and U simultaneously. Theoretical and experimental speciation studies showed the importance of adjusting the medium to HNO3/HF (0.5M/0.005M) to guarantee the stability over time of the analytes before removal of the matrix. Two preconcentration methods based on TRU® and TODGA® resins were optimized for the simultaneous isolation of Zr and U prior to Q ICP-MS measurements. Using TRU resin, alkali and alkali earth metals contained in the deep groundwater were removed with 2M HNO3 whereas Zr and U were recovered with a HNO3/NH4HC2O4 (0.02M/0.05M) medium. For the separation protocol based on TODGA resin, alkali and alkali earth metals were eliminated with 3M and 11M HNO3 while Zr and U were simultaneously stripped with a HNO3/HF (0.5M/0.2M) medium. The procedure optimized on TODGA resin was validated with the French AFNOR NF T90-210 standard by studying linearity, limits of quantification (LOQ) and separation yields. The LOQ was determined at 0.008μgL−1 for Zr and U after the separation. Both analytes were recovered quantitatively. Compared to a sample dilution implemented to reduce the matrix effects, the developed preconcentration method allowed improving the sensitivity up to a 20 fold factor for Zr and U measurements at trace level by Q ICP-MS.
Publication year: 2013
Source:Talanta, Volume 106
In the framework of trace element analysis by Q ICP-MS in a simulated deep Callovo-Oxfordian groundwater, separation procedures based on extraction chromatography were developed to eliminate the high salt contents and to concentrate Zr and U simultaneously. Theoretical and experimental speciation studies showed the importance of adjusting the medium to HNO3/HF (0.5M/0.005M) to guarantee the stability over time of the analytes before removal of the matrix. Two preconcentration methods based on TRU® and TODGA® resins were optimized for the simultaneous isolation of Zr and U prior to Q ICP-MS measurements. Using TRU resin, alkali and alkali earth metals contained in the deep groundwater were removed with 2M HNO3 whereas Zr and U were recovered with a HNO3/NH4HC2O4 (0.02M/0.05M) medium. For the separation protocol based on TODGA resin, alkali and alkali earth metals were eliminated with 3M and 11M HNO3 while Zr and U were simultaneously stripped with a HNO3/HF (0.5M/0.2M) medium. The procedure optimized on TODGA resin was validated with the French AFNOR NF T90-210 standard by studying linearity, limits of quantification (LOQ) and separation yields. The LOQ was determined at 0.008μgL−1 for Zr and U after the separation. Both analytes were recovered quantitatively. Compared to a sample dilution implemented to reduce the matrix effects, the developed preconcentration method allowed improving the sensitivity up to a 20 fold factor for Zr and U measurements at trace level by Q ICP-MS.
Highlights
► The analysis of Zr and U is proposed in a simulated deep groundwater by Q ICP-MS. ► The stability of both analytes in solution was guaranteed from speciation studies. ► TRU and TODGA-based preconcentration procedures were developed. ► The methods were validated with the French AFNOR NF T90-210 standard.Speciation analysis of inorganic arsenic in coal samples by microwave-assisted extraction and high performance liquid chromatography coupled to hydride generation atomic fluorescence spectrometry
18 January 2013,
09:51:33
15 March 2013
Publication year: 2013
Source:Talanta, Volume 106
A new method was developed for the speciation analysis of inorganic arsenic in coal samples by high performance liquid chromatography coupled to hydride generation atomic fluorescence spectrometry after microwave-assisted extraction. Effective extract of As(III) and As(V) in coal sample was achieved by 1.0molL−1H3PO4 and 0.1molL−1ascorbic acid. Under the optimized conditions, the limits of detection (LOD) were 0.01μgL−1 and 0.02μgL−1, the relative standard deviations (RSD) were 2.4% and 3.3% (c=10.0μgL−1, n=7), recoveries were 102.5% and 96.5% for As(III) and As(V). The proposed method was successfully applied for the determination of speciation of inorganic arsenic in coal samples and GBW11117 coal standard reference material with complex matrix.
Publication year: 2013
Source:Talanta, Volume 106
A new method was developed for the speciation analysis of inorganic arsenic in coal samples by high performance liquid chromatography coupled to hydride generation atomic fluorescence spectrometry after microwave-assisted extraction. Effective extract of As(III) and As(V) in coal sample was achieved by 1.0molL−1H3PO4 and 0.1molL−1ascorbic acid. Under the optimized conditions, the limits of detection (LOD) were 0.01μgL−1 and 0.02μgL−1, the relative standard deviations (RSD) were 2.4% and 3.3% (c=10.0μgL−1, n=7), recoveries were 102.5% and 96.5% for As(III) and As(V). The proposed method was successfully applied for the determination of speciation of inorganic arsenic in coal samples and GBW11117 coal standard reference material with complex matrix.
Highlights
► It is a new analytical method about speciation of inorganic arsenic in coal. ► It is an effective extraction method for inorganic arsenic in coal. ► New extraction system based on using H3PO4 and ascorbic acid as extractant.Characterization and quantification of 4-methylsterols and 4,4-dimethylsterols from Iberian pig subcutaneous fat by gas chromatography–mass spectrometry and gas chromatography–flame ionization detector and their use to authenticate the fattening systems
18 January 2013,
09:51:33
15 March 2013
Publication year: 2013
Source:Talanta, Volume 106
4-Methylsterols and 4,4-dimethylsterols of 47 samples of subcutaneous fat from Iberian pigs reared on two different fattening systems, “Extensive” and “Intensive”, have been analyzed by GC–MS and GC–FID. The lipids were extracted by melting the subcutaneous fat in a microwave oven. The unsaponifiable matter was fractionated by thin layer chromatography. Then, the analysis was performed on a capillary SPB-5 column (30m×0.25mm i.d., 0.15μm film thickness), with hydrogen as a carrier gas and using a flame ionization detector. n-eicosanol was used as internal standard for quantification of individual methylsterols. These compounds have been analyzed by GC–MS for their identification. The full scan of free and trimethyl silyl ethers was used as acquisition mode. Six compounds have been identified for the first time in this type of samples: (3β,4α,5α)-4-methyl-cholesta-7-en-3-ol, (3β,4α,5α)-4-methyl-cholesta-8(14)-en-3-ol, (3β,5α)-4,4-dimethyl-cholesta-8(14),24-dien-3-ol, (3β)-lanosta-8,24-dien-3-ol, (3β, 5α)-4,4-dimethyl-cholesta-8,14-dien-3-ol and (3β)-lanost-9(11),24-dien-3-ol. The samples were derivatized as trimethyl silyl ethers before their analysis by GC–FID. By using these compounds as chemical descriptors, pattern recognition techniques were applied to differentiate between extensive and intensive fattening systems of Iberian pig. Several pattern recognition techniques, such as principal component analysis, linear discriminant analysis, support vector machines, artificial neural networks, soft independent modeling of class analogy and k nearest neighbors, have been used in order to find out a suitable classification model. A multilayer perceptron artificial neural network based on the contents of the above mentioned compounds allowed the differentiation of the two fattening systems with an overall classification performance of 91.7%.
Publication year: 2013
Source:Talanta, Volume 106
4-Methylsterols and 4,4-dimethylsterols of 47 samples of subcutaneous fat from Iberian pigs reared on two different fattening systems, “Extensive” and “Intensive”, have been analyzed by GC–MS and GC–FID. The lipids were extracted by melting the subcutaneous fat in a microwave oven. The unsaponifiable matter was fractionated by thin layer chromatography. Then, the analysis was performed on a capillary SPB-5 column (30m×0.25mm i.d., 0.15μm film thickness), with hydrogen as a carrier gas and using a flame ionization detector. n-eicosanol was used as internal standard for quantification of individual methylsterols. These compounds have been analyzed by GC–MS for their identification. The full scan of free and trimethyl silyl ethers was used as acquisition mode. Six compounds have been identified for the first time in this type of samples: (3β,4α,5α)-4-methyl-cholesta-7-en-3-ol, (3β,4α,5α)-4-methyl-cholesta-8(14)-en-3-ol, (3β,5α)-4,4-dimethyl-cholesta-8(14),24-dien-3-ol, (3β)-lanosta-8,24-dien-3-ol, (3β, 5α)-4,4-dimethyl-cholesta-8,14-dien-3-ol and (3β)-lanost-9(11),24-dien-3-ol. The samples were derivatized as trimethyl silyl ethers before their analysis by GC–FID. By using these compounds as chemical descriptors, pattern recognition techniques were applied to differentiate between extensive and intensive fattening systems of Iberian pig. Several pattern recognition techniques, such as principal component analysis, linear discriminant analysis, support vector machines, artificial neural networks, soft independent modeling of class analogy and k nearest neighbors, have been used in order to find out a suitable classification model. A multilayer perceptron artificial neural network based on the contents of the above mentioned compounds allowed the differentiation of the two fattening systems with an overall classification performance of 91.7%.
Highlights
► Characterization and quantification of 4-methylsterols and 4,4-dimethylsterols. ► Differentiation between extensive and intensive fattening systems of Iberian pigs. ► Analysis by GC–MS in full scan mode and GC–FID. ► Pattern recognition techniques have been applied.A chromatographic method to analyze products from photo-oxidation of anthropogenic and biogenic mixtures of volatile organic compounds in smog chambers
18 January 2013,
09:51:33
15 March 2013
Publication year: 2013
Source:Talanta, Volume 106
A method for quantifying secondary organic aerosol compounds (SOA) and water soluble secondary organic aerosol compounds (WSOA) produced from photo-oxidation of complex mixtures of volatile organic compounds (VOCs) in smog chambers by gas chromatography/mass spectrometry (GC/MS) has been developed. This method employs a double extraction with water and methanol jointly to a double derivatization with N,O-bis (trimethylsilil) trifluoroacetamide (BSTFA) and O-(2,3,4,5,6)-pentafluorobenzyl-hydroxylamine hydrochloride (PFBHA) followed by an analysis performed by GC/MS. The analytical procedure complements other methodologies because it can analyze SOA and WSOA compounds simultaneously at trace levels. As application, the methodology was employed to quantify the organic composition of aerosols formed in a smog chamber as a result of photo-oxidation of two different mixtures of volatile organic compounds: an anthropogenic mixture and a biogenic mixture. The analytical method allowed us to quantify up to 17 SOA compounds at levels higher than 20ngm−3 with reasonable recovery and a precision below 11%. Values found for applicability, selectivity, linearity, precision, recovery, detection limit, quantification limit and sensitivity demonstrated that the methodology can be satisfactorily applied to quantify SOA and WSOA.
Publication year: 2013
Source:Talanta, Volume 106
A method for quantifying secondary organic aerosol compounds (SOA) and water soluble secondary organic aerosol compounds (WSOA) produced from photo-oxidation of complex mixtures of volatile organic compounds (VOCs) in smog chambers by gas chromatography/mass spectrometry (GC/MS) has been developed. This method employs a double extraction with water and methanol jointly to a double derivatization with N,O-bis (trimethylsilil) trifluoroacetamide (BSTFA) and O-(2,3,4,5,6)-pentafluorobenzyl-hydroxylamine hydrochloride (PFBHA) followed by an analysis performed by GC/MS. The analytical procedure complements other methodologies because it can analyze SOA and WSOA compounds simultaneously at trace levels. As application, the methodology was employed to quantify the organic composition of aerosols formed in a smog chamber as a result of photo-oxidation of two different mixtures of volatile organic compounds: an anthropogenic mixture and a biogenic mixture. The analytical method allowed us to quantify up to 17 SOA compounds at levels higher than 20ngm−3 with reasonable recovery and a precision below 11%. Values found for applicability, selectivity, linearity, precision, recovery, detection limit, quantification limit and sensitivity demonstrated that the methodology can be satisfactorily applied to quantify SOA and WSOA.
Highlights
► Authors report a GC/MS method to analyze simultaneously SOA and WSOA compounds. ► Validation of methodology was carried out. ► Products of the photo-oxidation of mixtures of VOCs in a smog chamber were studied. ► Up to 17 secondary organic compounds at trace level were quantified.Characterization of impurities in tylosin using dual liquid chromatography combined with ion trap mass spectrometry
18 January 2013,
09:51:33
15 March 2013
Publication year: 2013
Source:Talanta, Volume 106
Investigation of unknown impurities in a tylosin sample was performed using liquid chromatography coupled to mass spectrometry (LC/MS). Separation was performed according to the recently described LC-UV method of Ashenafi et al. (2011) [14]. This method was reported to have a good selectivity as it was able to separate the four main components of tylosin from the already known and 23 unknown impurities. However, as this method uses a mobile phase with non-volatile constituents, direct characterization of these impurities using LC/MS was not possible. The impurity fractions were therefore first collected and then desalted before sending them to the MS. Identification of the impurities in the tylosin sample was performed with a quadruple ion trap (IT) MS, with an electrospray ionization (ESI) source in the positive ion mode. The structure of the impurities was deduced by comparing their fragmentation pattern with those of the main components of tylosin. As several peaks in the LC-UV method contained multiple compounds, using this method in total 41 new impurities were (partly) characterized.
Publication year: 2013
Source:Talanta, Volume 106
Investigation of unknown impurities in a tylosin sample was performed using liquid chromatography coupled to mass spectrometry (LC/MS). Separation was performed according to the recently described LC-UV method of Ashenafi et al. (2011) [14]. This method was reported to have a good selectivity as it was able to separate the four main components of tylosin from the already known and 23 unknown impurities. However, as this method uses a mobile phase with non-volatile constituents, direct characterization of these impurities using LC/MS was not possible. The impurity fractions were therefore first collected and then desalted before sending them to the MS. Identification of the impurities in the tylosin sample was performed with a quadruple ion trap (IT) MS, with an electrospray ionization (ESI) source in the positive ion mode. The structure of the impurities was deduced by comparing their fragmentation pattern with those of the main components of tylosin. As several peaks in the LC-UV method contained multiple compounds, using this method in total 41 new impurities were (partly) characterized.
Highlights
► Investigation of the unknown impurities in tylosin was carried out. ► LC-ion trap MS was used for the characterization. ► Fragmentation of two of the four main components is described for the first time. ► Forty-one UNK impurities that were never described before were (partially) characterized.Bk and Cf chromatographic separation and 249Bk/248Cm and 249Cf/248Cm elemental ratios determination by inductively coupled plasma quadrupole mass spectrometry
18 January 2013,
09:51:33
15 March 2013
Publication year: 2013
Source:Talanta, Volume 106
The French Atomic Energy Commission has carried out several experiments for the study of minor-actinide transmutation processes in high intensity thermal neutron flux. In this context a Cm sample enriched in 248Cm (∼97%) was irradiated in a thermal neutron flux at the High Flux Reactor (HFR) of the Laue–Langevin Institute (ILL). The precise and accurate determination of Cf isotope ratios and of 249Bk/248Cm and 249Cf/248Cm elemental ratios in the 248Cm irradiated sample is crucial for the calculation of actinide neutron capture cross-sections. This work describes an analytical procedure for the separation and the isotope ratio measurement of Bk and Cf in the irradiated sample. The Bk and Cf separation is based on a lanthanides separation protocol previously developed by the laboratory. Well-defined retention times for Bk and Cf were obtained by coupling the Ionic Chromatography (IC) with an ICP-QMS. All conditions of element separation by IC and the different steps of the analytical protocol in order to obtain the isotopic and elemental ratios are presented. Relative uncertainties of Cf isotopic ratios range from 0.3% to 0.5% and the uncertainty of the 249Bk/248Cm and 249Cf/248Cm elemental ratios are respectively 6.1% and 3.2%. This level of uncertainty for both isotopic and elemental ratios is in perfect agreement with the requirement for transmutation studies.
Publication year: 2013
Source:Talanta, Volume 106
The French Atomic Energy Commission has carried out several experiments for the study of minor-actinide transmutation processes in high intensity thermal neutron flux. In this context a Cm sample enriched in 248Cm (∼97%) was irradiated in a thermal neutron flux at the High Flux Reactor (HFR) of the Laue–Langevin Institute (ILL). The precise and accurate determination of Cf isotope ratios and of 249Bk/248Cm and 249Cf/248Cm elemental ratios in the 248Cm irradiated sample is crucial for the calculation of actinide neutron capture cross-sections. This work describes an analytical procedure for the separation and the isotope ratio measurement of Bk and Cf in the irradiated sample. The Bk and Cf separation is based on a lanthanides separation protocol previously developed by the laboratory. Well-defined retention times for Bk and Cf were obtained by coupling the Ionic Chromatography (IC) with an ICP-QMS. All conditions of element separation by IC and the different steps of the analytical protocol in order to obtain the isotopic and elemental ratios are presented. Relative uncertainties of Cf isotopic ratios range from 0.3% to 0.5% and the uncertainty of the 249Bk/248Cm and 249Cf/248Cm elemental ratios are respectively 6.1% and 3.2%. This level of uncertainty for both isotopic and elemental ratios is in perfect agreement with the requirement for transmutation studies.
Highlights
► Bk and Cf separation by Ionic Chromatography in a 248Cm irradiated sample. ► This separation was performed by ICP-QMS/IC coupling. ► Isotope ratio composition of the purified fractions by ICP-QMS. ► With work we contribute more precise data for actinide neutron capture cross-sectionsRecent applications of molecular imprinted polymers for enantio-selective recognition
18 January 2013,
09:51:33
15 March 2013
Publication year: 2013
Source:Talanta, Volume 106
Molecular imprinted polymer (MIP) techniques have been increasingly used in a variety of fields including chromatography, sample pretreatment, purification, sensors, drug delivery, and catalysts, etc. MIP is a specific artificial receptor that shows favored affinity to the template molecule. The cavities of the template are produced by carrying out polymerization of a reaction mixture followed by eliminating the template molecules by washing. Various forms of MIP materials have been prepared for diverse applications including irregularly ground particles, regular spherical particles, nanoparticles, monoliths in a stainless steel or capillary column, open tubular layers in capillaries, membranes, surface attached thin layers, and composites, etc. When an enantiomer is used as the template, then the resulting MIP can show capability of enantiomeric recognition between the pair of enantiomers. In this review, progresses in applications of enantio-selective recognition by MIPs will be critically reviewed for the recent period since 2007.
Publication year: 2013
Source:Talanta, Volume 106
Molecular imprinted polymer (MIP) techniques have been increasingly used in a variety of fields including chromatography, sample pretreatment, purification, sensors, drug delivery, and catalysts, etc. MIP is a specific artificial receptor that shows favored affinity to the template molecule. The cavities of the template are produced by carrying out polymerization of a reaction mixture followed by eliminating the template molecules by washing. Various forms of MIP materials have been prepared for diverse applications including irregularly ground particles, regular spherical particles, nanoparticles, monoliths in a stainless steel or capillary column, open tubular layers in capillaries, membranes, surface attached thin layers, and composites, etc. When an enantiomer is used as the template, then the resulting MIP can show capability of enantiomeric recognition between the pair of enantiomers. In this review, progresses in applications of enantio-selective recognition by MIPs will be critically reviewed for the recent period since 2007.
Highlights
► The most recent enantio-selective applications of MIPS are introduced. ► The general trends and future perspectives are given. ► The amazing results of open tubular MIP CEC studies are included.Evaluation of different extraction procedures for determination of organic Mercury species in petroleum by high performance liquid chromatography coupled with cold vapor atomic fluorescence spectrometry
18 January 2013,
09:51:33
15 March 2013
Publication year: 2013
Source:Talanta, Volume 106
An extraction procedure for extracting organic mercury species including methylmercury (MeHg) and ethylmercury (EtHg) from petroleum samples was developed. Three extraction methods (shaking, ultrasonic and microwave assisted extraction) using different extraction solvents (TMAH, KOH/CH3OH, HCl and acidic CuSO4/KBr) were investigated by comparing the extraction efficiency of the organic mercury species. Microwave assisted extraction at 60W for 5min using TMAH (tetramethylammonium hydroxide, 25%, m/v) provided the most satisfactory extraction efficiency for MeHg and EtHg in petroleum at 86.7%±3.4% and 70.6%±5.9%, respectively. Speciation analysis of mercury was done by on-line coupling of high performance liquid chromatography with cold vapor generation atomic fluorescence spectrometry (HPLC-CV-AFS). The proposed method was successfully applied to analyze several crude oil and light oil samples. The concentrations of MeHg ranged from under detection limit to 0.515ngg−1, whereas EtHg was not detected in the samples. This method can be a very useful tool in evaluating the risk of mercury emissions from petroleum.
Publication year: 2013
Source:Talanta, Volume 106
An extraction procedure for extracting organic mercury species including methylmercury (MeHg) and ethylmercury (EtHg) from petroleum samples was developed. Three extraction methods (shaking, ultrasonic and microwave assisted extraction) using different extraction solvents (TMAH, KOH/CH3OH, HCl and acidic CuSO4/KBr) were investigated by comparing the extraction efficiency of the organic mercury species. Microwave assisted extraction at 60W for 5min using TMAH (tetramethylammonium hydroxide, 25%, m/v) provided the most satisfactory extraction efficiency for MeHg and EtHg in petroleum at 86.7%±3.4% and 70.6%±5.9%, respectively. Speciation analysis of mercury was done by on-line coupling of high performance liquid chromatography with cold vapor generation atomic fluorescence spectrometry (HPLC-CV-AFS). The proposed method was successfully applied to analyze several crude oil and light oil samples. The concentrations of MeHg ranged from under detection limit to 0.515ngg−1, whereas EtHg was not detected in the samples. This method can be a very useful tool in evaluating the risk of mercury emissions from petroleum.
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