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Analytica Chimica Acta (v.684, #1-2)
Determination of low levels of cadmium ions by the under potential deposition on a self-assembled monolayer on gold electrode by Tomer Noyhouzer; Daniel Mandler (pp. 1-7).
The electrochemical determination of low levels of Cd using a self-assembled monolayer (SAM) modified Au electrode is reported. Determination was based on the stripping of Cd, which was deposited by under potential deposition (UPD). A series of short alkanethiol SAMs bearing different end groups, i.e., sulfonate, carboxylate and ammonium, were examined. Lowest level of detection (ca. 50ngL−1) was achieved with a 3-mercaptopropionic acid (MPA) monolayer using subtractive anodic square wave voltammetry (SASV).Additional surface methods, namely, reductive desorption and X-ray photoelectron spectroscopy, were applied to determine the interfacial structure of the electrodeposited Cd on the modified electrodes. We conclude that the deposited Cd forms a monoatomic layer, which bridges between the gold surface and the alkanethiol monolayer associating with both the gold and the sulfur atoms.
Keywords: Cadmium; Under potential deposition; Self-assembled monolayer; Subtractive anodic square wave voltammetry
Determination of low levels of cadmium ions by the under potential deposition on a self-assembled monolayer on gold electrode by Tomer Noyhouzer; Daniel Mandler (pp. 1-7).
The electrochemical determination of low levels of Cd using a self-assembled monolayer (SAM) modified Au electrode is reported. Determination was based on the stripping of Cd, which was deposited by under potential deposition (UPD). A series of short alkanethiol SAMs bearing different end groups, i.e., sulfonate, carboxylate and ammonium, were examined. Lowest level of detection (ca. 50ngL−1) was achieved with a 3-mercaptopropionic acid (MPA) monolayer using subtractive anodic square wave voltammetry (SASV).Additional surface methods, namely, reductive desorption and X-ray photoelectron spectroscopy, were applied to determine the interfacial structure of the electrodeposited Cd on the modified electrodes. We conclude that the deposited Cd forms a monoatomic layer, which bridges between the gold surface and the alkanethiol monolayer associating with both the gold and the sulfur atoms.
Keywords: Cadmium; Under potential deposition; Self-assembled monolayer; Subtractive anodic square wave voltammetry
Determination of low levels of cadmium ions by the under potential deposition on a self-assembled monolayer on gold electrode by Tomer Noyhouzer; Daniel Mandler (pp. 1-7).
The electrochemical determination of low levels of Cd using a self-assembled monolayer (SAM) modified Au electrode is reported. Determination was based on the stripping of Cd, which was deposited by under potential deposition (UPD). A series of short alkanethiol SAMs bearing different end groups, i.e., sulfonate, carboxylate and ammonium, were examined. Lowest level of detection (ca. 50ngL−1) was achieved with a 3-mercaptopropionic acid (MPA) monolayer using subtractive anodic square wave voltammetry (SASV).Additional surface methods, namely, reductive desorption and X-ray photoelectron spectroscopy, were applied to determine the interfacial structure of the electrodeposited Cd on the modified electrodes. We conclude that the deposited Cd forms a monoatomic layer, which bridges between the gold surface and the alkanethiol monolayer associating with both the gold and the sulfur atoms.
Keywords: Cadmium; Under potential deposition; Self-assembled monolayer; Subtractive anodic square wave voltammetry
Recent and potential developments in the analysis of urine: A review by D. Ryan; K. Robards; P.D. Prenzler; Megan Kendall (pp. 8-20).
Analysis of urine is a widely used diagnostic tool that traditionally measured one or, at most, a few metabolites. However, the recognition of the need for a holistic approach to metabolism led to the application of metabolomics to urine for disease diagnostics. This review looks at various aspects of urinalysis including sampling and traditional approaches before reviewing recent developments using metabolomics. Spectrometric approaches are covered briefly since there are already a number of very good reviews on NMR spectroscopy and mass spectrometry and other spectrometries are not as highly developed in their applications to metabolomics. On the other hand, there has been a recent surge in chromatographic applications dedicated to characterising the human urinary metabolome. While developments in the analysis of urine encompassing both classical approaches of urinalysis and metabolomics are covered, it must be emphasized that these approaches are not orthogonal – they both have their uses and are complementary. Regardless, the need to normalise analytical data remains an important impediment.
Keywords: Chromatography; Creatinine; LC; Normalisation; Spectrometry
Recent and potential developments in the analysis of urine: A review by D. Ryan; K. Robards; P.D. Prenzler; Megan Kendall (pp. 8-20).
Analysis of urine is a widely used diagnostic tool that traditionally measured one or, at most, a few metabolites. However, the recognition of the need for a holistic approach to metabolism led to the application of metabolomics to urine for disease diagnostics. This review looks at various aspects of urinalysis including sampling and traditional approaches before reviewing recent developments using metabolomics. Spectrometric approaches are covered briefly since there are already a number of very good reviews on NMR spectroscopy and mass spectrometry and other spectrometries are not as highly developed in their applications to metabolomics. On the other hand, there has been a recent surge in chromatographic applications dedicated to characterising the human urinary metabolome. While developments in the analysis of urine encompassing both classical approaches of urinalysis and metabolomics are covered, it must be emphasized that these approaches are not orthogonal – they both have their uses and are complementary. Regardless, the need to normalise analytical data remains an important impediment.
Keywords: Chromatography; Creatinine; LC; Normalisation; Spectrometry
Typing of unknown microorganisms based on quantitative analysis of fatty acids by mass spectrometry and hierarchical clustering by Tingting Li; Ling Dai; Lun Li; Xuejiao Hu; Linjie Dong; Jianjian Li; Sule Khalfan Salim; Jieying Fu; Hongying Zhong (pp. 8-16).
Rapid identification of unknown microorganisms of clinical and agricultural importance is not only critical for accurate diagnosis of infections but also essential for appropriate and prompt treatment. We describe here a rapid method for microorganisms typing based on quantitative analysis of fatty acids by iFAT approach (Isotope-coded Fatty Acid Transmethylation). In this work, lyophilized cell lysates were directly mixed with 0.5M NaOH solution in d3-methanol and n-hexane. After 1min of ultrasonication, the top n-hexane layer was combined with a mixture of standard d0-methanol derived fatty acid methylesters with known concentration. Measurement of intensity ratios of d3/d0 labeled fragment ion and molecular ion pairs at the corresponding target fatty acids provides a quantitative basis for hierarchical clustering. In the resultant dendrogram, the Euclidean distance between unknown species and known species quantitatively reveals their differences or shared similarities in fatty acid related pathways. It is of particular interest to apply this method for typing fungal species because fungi has distinguished lipid biosynthetic pathways that have been targeted for lots of drugs or fungicides compared with bacteria and animals. The proposed method has no dependence on the availability of genome or proteome databases. Therefore, it is can be applicable for a broad range of unknown microorganisms or mutant species.
Keywords: Microorganism identification; Fatty acids; Hierarchical clustering; Mass spectrometry; Stable isotope labeling
Recent and potential developments in the analysis of urine: A review by D. Ryan; K. Robards; P.D. Prenzler; Megan Kendall (pp. 17-29).
Analysis of urine is a widely used diagnostic tool that traditionally measured one or, at most, a few metabolites. However, the recognition of the need for a holistic approach to metabolism led to the application of metabolomics to urine for disease diagnostics. This review looks at various aspects of urinalysis including sampling and traditional approaches before reviewing recent developments using metabolomics. Spectrometric approaches are covered briefly since there are already a number of very good reviews on NMR spectroscopy and mass spectrometry and other spectrometries are not as highly developed in their applications to metabolomics. On the other hand, there has been a recent surge in chromatographic applications dedicated to characterising the human urinary metabolome. While developments in the analysis of urine encompassing both classical approaches of urinalysis and metabolomics are covered, it must be emphasized that these approaches are not orthogonal – they both have their uses and are complementary. Regardless, the need to normalise analytical data remains an important impediment.
Keywords: Chromatography; Creatinine; LC; Normalisation; Spectrometry
Trends in flow-based analytical methods applied to pesticide detection: A review by E.J. Llorent-Martínez; P. Ortega-Barrales; M.L. Fernández-de Córdova; A. Ruiz-Medina (pp. 21-30).
Recent applications of flow-based analytical methods for pesticide determinations are reviewed. This review is focused on the description of electrochemical and optical flow sensors, describing the most relevant applications in this field. The different approaches employed up to date in electrochemical biosensors, together with the possible modifications in the flow methodology and the development of multiparameter flow-through optosensors have also been extensively described. Advantages, handicaps and current trends of each detection technique are critically discussed. The article ends up with a comparison between flow-based analytical methods and chromatography when applied to pesticide determination.
Keywords: Optosensor; Electrochemical sensor; Flow analysis; Pesticides; Multicommutation
Trends in flow-based analytical methods applied to pesticide detection: A review by E.J. Llorent-Martínez; P. Ortega-Barrales; M.L. Fernández-de Córdova; A. Ruiz-Medina (pp. 21-30).
Recent applications of flow-based analytical methods for pesticide determinations are reviewed. This review is focused on the description of electrochemical and optical flow sensors, describing the most relevant applications in this field. The different approaches employed up to date in electrochemical biosensors, together with the possible modifications in the flow methodology and the development of multiparameter flow-through optosensors have also been extensively described. Advantages, handicaps and current trends of each detection technique are critically discussed. The article ends up with a comparison between flow-based analytical methods and chromatography when applied to pesticide determination.
Keywords: Optosensor; Electrochemical sensor; Flow analysis; Pesticides; Multicommutation
Trends in flow-based analytical methods applied to pesticide detection: A review by E.J. Llorent-Martínez; P. Ortega-Barrales; M.L. Fernández-de Córdova; A. Ruiz-Medina (pp. 30-39).
Recent applications of flow-based analytical methods for pesticide determinations are reviewed. This review is focused on the description of electrochemical and optical flow sensors, describing the most relevant applications in this field. The different approaches employed up to date in electrochemical biosensors, together with the possible modifications in the flow methodology and the development of multiparameter flow-through optosensors have also been extensively described. Advantages, handicaps and current trends of each detection technique are critically discussed. The article ends up with a comparison between flow-based analytical methods and chromatography when applied to pesticide determination.
Keywords: Optosensor; Electrochemical sensor; Flow analysis; Pesticides; Multicommutation
Sequential automated fusion/extraction chromatography methodology for the dissolution of uranium in environmental samples for mass spectrometric determination by Alex Milliard; Myriam Durand-Jézéquel; Dominic Larivière (pp. 31-37).
An improved methodology has been developed, based on dissolution by automated fusion followed by extraction chromatography for the detection and quantification of uranium in environmental matrices by mass spectrometry. A rapid fusion protocol (<8min) was investigated for the complete dissolution of various samples. It could be preceded, if required, by an effective ashing procedure using the M4 fluxer and a newly designed platinum lid. Complete dissolution of the sample was observed and measured using standard reference materials (SRMs) and experimental data show no evidence of cross-contamination of crucibles when LiBO2/LiBr melts were used. The use of a M4 fusion unit also improved repeatability in sample preparation over muffle furnace fusion. Instrumental issues originating from the presence of high salt concentrations in the digestate after lithium metaborate fusion was also mitigated using an extraction chromatography (EXC) protocol aimed at removing lithium and interfering matrix constituants prior to the elution of uranium. The sequential methodology, which can be performed simultaneously on three samples, requires less than 20min per sample for fusion and separation. It was successfully coupled to inductively coupled plasma mass spectrometry (ICP-MS) achieving detection limits below 100pgkg−1 for 5–300mg of sample.
Keywords: Lithium metaborate fusion; UTEVA extraction resin; Inductively coupled plasma mass spectrometry; Uranium
Sequential automated fusion/extraction chromatography methodology for the dissolution of uranium in environmental samples for mass spectrometric determination by Alex Milliard; Myriam Durand-Jézéquel; Dominic Larivière (pp. 31-37).
An improved methodology has been developed, based on dissolution by automated fusion followed by extraction chromatography for the detection and quantification of uranium in environmental matrices by mass spectrometry. A rapid fusion protocol (<8min) was investigated for the complete dissolution of various samples. It could be preceded, if required, by an effective ashing procedure using the M4 fluxer and a newly designed platinum lid. Complete dissolution of the sample was observed and measured using standard reference materials (SRMs) and experimental data show no evidence of cross-contamination of crucibles when LiBO2/LiBr melts were used. The use of a M4 fusion unit also improved repeatability in sample preparation over muffle furnace fusion. Instrumental issues originating from the presence of high salt concentrations in the digestate after lithium metaborate fusion was also mitigated using an extraction chromatography (EXC) protocol aimed at removing lithium and interfering matrix constituants prior to the elution of uranium. The sequential methodology, which can be performed simultaneously on three samples, requires less than 20min per sample for fusion and separation. It was successfully coupled to inductively coupled plasma mass spectrometry (ICP-MS) achieving detection limits below 100pgkg−1 for 5–300mg of sample.
Keywords: Lithium metaborate fusion; UTEVA extraction resin; Inductively coupled plasma mass spectrometry; Uranium
Quantitative depth profile analysis of metallic coatings by pulsed radiofrequency glow discharge optical emission spectrometry by Pascal Sánchez; Beatriz Fernández; Armando Menéndez; Jaime Orejas; Rosario Pereiro; Alfredo Sanz-Medel (pp. 38-44).
In recent years particular effort is being devoted towards the development of pulsed GDs because this powering operation mode could offer important analytical advantages. However, the capabilities of radiofrequency (rf) powered glow discharge (GD) in pulsed mode coupled to optical emission spectrometry (OES) for real depth profile quantification has not been demonstrated yet. Therefore, the first part of this work is focussed on assessing the expected advantages of the pulsed GD mode, in comparison with its continuous mode counterpart, in terms of analytical emission intensities and emission yield parameters. Then, the capability of pulsed rf-GD-OES for determination of thickness and compositional depth profiles is demonstrated by resorting to a simple multi-matrix calibration procedure. A rf forward power of 50W, a pressure of 600Pa, 1000Hz pulse frequency and 50% duty cycle were selected. The quantification procedure used was validated by analysing conductive layers of thicknesses ranging from a few tens of nanometer up to about 20μm and varied compositions (hot-dipped zinc, galvanneal, back contact of thin film photovoltaic solar cells and tinplates).
Keywords: Pulsed glow discharge; Optical emission spectrometry; Depth profile analysis; Coatings
Quantitative depth profile analysis of metallic coatings by pulsed radiofrequency glow discharge optical emission spectrometry by Pascal Sánchez; Beatriz Fernández; Armando Menéndez; Jaime Orejas; Rosario Pereiro; Alfredo Sanz-Medel (pp. 38-44).
In recent years particular effort is being devoted towards the development of pulsed GDs because this powering operation mode could offer important analytical advantages. However, the capabilities of radiofrequency (rf) powered glow discharge (GD) in pulsed mode coupled to optical emission spectrometry (OES) for real depth profile quantification has not been demonstrated yet. Therefore, the first part of this work is focussed on assessing the expected advantages of the pulsed GD mode, in comparison with its continuous mode counterpart, in terms of analytical emission intensities and emission yield parameters. Then, the capability of pulsed rf-GD-OES for determination of thickness and compositional depth profiles is demonstrated by resorting to a simple multi-matrix calibration procedure. A rf forward power of 50W, a pressure of 600Pa, 1000Hz pulse frequency and 50% duty cycle were selected. The quantification procedure used was validated by analysing conductive layers of thicknesses ranging from a few tens of nanometer up to about 20μm and varied compositions (hot-dipped zinc, galvanneal, back contact of thin film photovoltaic solar cells and tinplates).
Keywords: Pulsed glow discharge; Optical emission spectrometry; Depth profile analysis; Coatings
Sequential automated fusion/extraction chromatography methodology for the dissolution of uranium in environmental samples for mass spectrometric determination by Alex Milliard; Myriam Durand-Jézéquel; Dominic Larivière (pp. 40-46).
An improved methodology has been developed, based on dissolution by automated fusion followed by extraction chromatography for the detection and quantification of uranium in environmental matrices by mass spectrometry. A rapid fusion protocol (<8min) was investigated for the complete dissolution of various samples. It could be preceded, if required, by an effective ashing procedure using the M4 fluxer and a newly designed platinum lid. Complete dissolution of the sample was observed and measured using standard reference materials (SRMs) and experimental data show no evidence of cross-contamination of crucibles when LiBO2/LiBr melts were used. The use of a M4 fusion unit also improved repeatability in sample preparation over muffle furnace fusion. Instrumental issues originating from the presence of high salt concentrations in the digestate after lithium metaborate fusion was also mitigated using an extraction chromatography (EXC) protocol aimed at removing lithium and interfering matrix constituants prior to the elution of uranium. The sequential methodology, which can be performed simultaneously on three samples, requires less than 20min per sample for fusion and separation. It was successfully coupled to inductively coupled plasma mass spectrometry (ICP-MS) achieving detection limits below 100pgkg−1 for 5–300mg of sample.
Keywords: Lithium metaborate fusion; UTEVA extraction resin; Inductively coupled plasma mass spectrometry; Uranium
Separation of trace amount of silver using dispersive liquid–liquid based on solidification of floating organic drop microextraction by Daryoush Afzali; Ali Reza Mohadesi; Behnoosh Bahadori Jahromi; Masoumeh Falahnejad (pp. 45-49).
In the present work, dispersive liquid–liquid microextraction based on solidification of floating organic drop was developed as a simple and rapid technique for separation of silver ions from aqueous samples. In this technique, 700μL 0.02% of 5-(4′-dimethylamino benzyliden)-rhodanine (chelating agent) was added into the 10mL analyte sample in a test tube and 30.0μL 1-undecanol (extraction solvent) was injected shortly thereafter. The test tubes were sonicated, centrifuged and then some effective parameters on extraction and complex formation, such as type and volume of extraction and disperser solvent, pH, the amount of chelating agent and extraction time were optimized. The effect of the interfering ions on the analytes recovery was also investigated. The calibration graph was linear in the range of 0.10–10.0ngmL−1 with detection limit of 0.056ngmL−1 ( n=8). The relative standard deviation (RSD) was±4.3% ( n=8, C=5.0ngmL−1) and the enrichment factor was 250.0. The proposed method was applied for extraction and determination of silver in different water samples.
Keywords: Dispersive liquid–liquid microextraction; Solidification; Silver determination; Water analysis; Separation; Preconcentration
Separation of trace amount of silver using dispersive liquid–liquid based on solidification of floating organic drop microextraction by Daryoush Afzali; Ali Reza Mohadesi; Behnoosh Bahadori Jahromi; Masoumeh Falahnejad (pp. 45-49).
In the present work, dispersive liquid–liquid microextraction based on solidification of floating organic drop was developed as a simple and rapid technique for separation of silver ions from aqueous samples. In this technique, 700μL 0.02% of 5-(4′-dimethylamino benzyliden)-rhodanine (chelating agent) was added into the 10mL analyte sample in a test tube and 30.0μL 1-undecanol (extraction solvent) was injected shortly thereafter. The test tubes were sonicated, centrifuged and then some effective parameters on extraction and complex formation, such as type and volume of extraction and disperser solvent, pH, the amount of chelating agent and extraction time were optimized. The effect of the interfering ions on the analytes recovery was also investigated. The calibration graph was linear in the range of 0.10–10.0ngmL−1 with detection limit of 0.056ngmL−1 ( n=8). The relative standard deviation (RSD) was±4.3% ( n=8, C=5.0ngmL−1) and the enrichment factor was 250.0. The proposed method was applied for extraction and determination of silver in different water samples.
Keywords: Dispersive liquid–liquid microextraction; Solidification; Silver determination; Water analysis; Separation; Preconcentration
Quantitative depth profile analysis of metallic coatings by pulsed radiofrequency glow discharge optical emission spectrometry by Pascal Sánchez; Beatriz Fernández; Armando Menéndez; Jaime Orejas; Rosario Pereiro; Alfredo Sanz-Medel (pp. 47-53).
In recent years particular effort is being devoted towards the development of pulsed GDs because this powering operation mode could offer important analytical advantages. However, the capabilities of radiofrequency (rf) powered glow discharge (GD) in pulsed mode coupled to optical emission spectrometry (OES) for real depth profile quantification has not been demonstrated yet. Therefore, the first part of this work is focussed on assessing the expected advantages of the pulsed GD mode, in comparison with its continuous mode counterpart, in terms of analytical emission intensities and emission yield parameters. Then, the capability of pulsed rf-GD-OES for determination of thickness and compositional depth profiles is demonstrated by resorting to a simple multi-matrix calibration procedure. A rf forward power of 50W, a pressure of 600Pa, 1000Hz pulse frequency and 50% duty cycle were selected. The quantification procedure used was validated by analysing conductive layers of thicknesses ranging from a few tens of nanometer up to about 20μm and varied compositions (hot-dipped zinc, galvanneal, back contact of thin film photovoltaic solar cells and tinplates).
Keywords: Pulsed glow discharge; Optical emission spectrometry; Depth profile analysis; Coatings
Fully automated determination of parabens, triclosan and methyl triclosan in wastewater by microextraction by packed sorbents and gas chromatography–mass spectrometry by Iria González-Mariño; José Benito Quintana; Isaac Rodríguez; Steffi Schrader; Monika Moeder (pp. 50-57).
A fully automated method for the determination of triclosan (TCS), its derivative methyl triclosan (MeTCS) and six parabens (esters of 4-hydroxybenzoic acid) including branched and linear isomers of propyl ( i-PrP and n-PrP) and butyl paraben ( i-BuP and n-BuP) in sewage water samples is presented. The procedure includes analytes enrichment by microextraction by packed sorbent (MEPS) coupled at-line to large volume injection-gas chromatography–mass spectrometry (LVI-GC–MS). Under optimised conditions, compounds were extracted from 2mL samples, adjusted at pH 3, using a C18 MEPS-sorbent. Adsorbed analytes were eluted directly into the Programmable Temperature Vaporizer (PTV) injector of the chromatograph with 2×25μL of ethyl acetate. They were quantified using standard solutions in ultrapure water submitted to the same sample enrichment process as real sewage water samples. After signal normalisation using isotopic labelled species as internal surrogates, no differences were noticed among the extraction efficiency for sewage and ultrapure water; moreover, the proposed method reported lineal calibration curves from 0.1 to 10ngmL−1, relative standard deviations (%RSD) between 2 and 7.1% and limits of detection (LODs) varying from 0.001 to 0.015ngmL−1 in ultrapure water and from 0.02 to 0.59ngmL−1 in the most complex sample (raw wastewater).
Keywords: Biocides; Extraction techniques; Microextraction; Automation; Gas chromatography–mass spectrometry; Water analysis
Fully automated determination of parabens, triclosan and methyl triclosan in wastewater by microextraction by packed sorbents and gas chromatography–mass spectrometry by Iria González-Mariño; José Benito Quintana; Isaac Rodríguez; Steffi Schrader; Monika Moeder (pp. 50-57).
A fully automated method for the determination of triclosan (TCS), its derivative methyl triclosan (MeTCS) and six parabens (esters of 4-hydroxybenzoic acid) including branched and linear isomers of propyl ( i-PrP and n-PrP) and butyl paraben ( i-BuP and n-BuP) in sewage water samples is presented. The procedure includes analytes enrichment by microextraction by packed sorbent (MEPS) coupled at-line to large volume injection-gas chromatography–mass spectrometry (LVI-GC–MS). Under optimised conditions, compounds were extracted from 2mL samples, adjusted at pH 3, using a C18 MEPS-sorbent. Adsorbed analytes were eluted directly into the Programmable Temperature Vaporizer (PTV) injector of the chromatograph with 2×25μL of ethyl acetate. They were quantified using standard solutions in ultrapure water submitted to the same sample enrichment process as real sewage water samples. After signal normalisation using isotopic labelled species as internal surrogates, no differences were noticed among the extraction efficiency for sewage and ultrapure water; moreover, the proposed method reported lineal calibration curves from 0.1 to 10ngmL−1, relative standard deviations (%RSD) between 2 and 7.1% and limits of detection (LODs) varying from 0.001 to 0.015ngmL−1 in ultrapure water and from 0.02 to 0.59ngmL−1 in the most complex sample (raw wastewater).
Keywords: Biocides; Extraction techniques; Microextraction; Automation; Gas chromatography–mass spectrometry; Water analysis
Separation of trace amount of silver using dispersive liquid–liquid based on solidification of floating organic drop microextraction by Daryoush Afzali; Ali Reza Mohadesi; Behnoosh Bahadori Jahromi; Masoumeh Falahnejad (pp. 54-58).
In the present work, dispersive liquid–liquid microextraction based on solidification of floating organic drop was developed as a simple and rapid technique for separation of silver ions from aqueous samples. In this technique, 700μL 0.02% of 5-(4′-dimethylamino benzyliden)-rhodanine (chelating agent) was added into the 10mL analyte sample in a test tube and 30.0μL 1-undecanol (extraction solvent) was injected shortly thereafter. The test tubes were sonicated, centrifuged and then some effective parameters on extraction and complex formation, such as type and volume of extraction and disperser solvent, pH, the amount of chelating agent and extraction time were optimized. The effect of the interfering ions on the analytes recovery was also investigated. The calibration graph was linear in the range of 0.10–10.0ngmL−1 with detection limit of 0.056ngmL−1 ( n=8). The relative standard deviation (RSD) was±4.3% ( n=8, C=5.0ngmL−1) and the enrichment factor was 250.0. The proposed method was applied for extraction and determination of silver in different water samples.
Keywords: Dispersive liquid–liquid microextraction; Solidification; Silver determination; Water analysis; Separation; Preconcentration
Headspace-solid phase microextraction of selenium(IV) from human blood and water samples using polypyrrole film and analysis with ion mobility spectrometry by Parvin Shahdousti; Naader Alizadeh (pp. 58-62).
Headspace-solid phase microextraction (HS-SPME) with a polypyrrole (PPy)-coated fiber was applied as a sample preparation method for determination of selenite [Se(IV)] following derivatization with 1,2-diaminobenzene to convert into the piaselenol form and analysis by ion mobility spectrometry (IMS). The HS-SPME–IMS method presents good repeatability (RSDs <6%), simplicity, good sensitivity and short analysis times. The influence of the various analytical parameters on microextraction procedure, i.e. ligand concentration, pH, ionic strength, equilibrium time and temperature has been evaluated and optimized. The calibration graph was linear in the range of 20–320ngmL−1 with a detection limit of 12ngmL−1. The method was applied for determination of selenium in human serum and environmental surface water samples with satisfactory recovery.
Keywords: Selenium; Headspace-solid phase microextraction; Polypyrrole; Ion mobility spectrometry; Human serum; Water samples
Headspace-solid phase microextraction of selenium(IV) from human blood and water samples using polypyrrole film and analysis with ion mobility spectrometry by Parvin Shahdousti; Naader Alizadeh (pp. 58-62).
Headspace-solid phase microextraction (HS-SPME) with a polypyrrole (PPy)-coated fiber was applied as a sample preparation method for determination of selenite [Se(IV)] following derivatization with 1,2-diaminobenzene to convert into the piaselenol form and analysis by ion mobility spectrometry (IMS). The HS-SPME–IMS method presents good repeatability (RSDs <6%), simplicity, good sensitivity and short analysis times. The influence of the various analytical parameters on microextraction procedure, i.e. ligand concentration, pH, ionic strength, equilibrium time and temperature has been evaluated and optimized. The calibration graph was linear in the range of 20–320ngmL−1 with a detection limit of 12ngmL−1. The method was applied for determination of selenium in human serum and environmental surface water samples with satisfactory recovery.
Keywords: Selenium; Headspace-solid phase microextraction; Polypyrrole; Ion mobility spectrometry; Human serum; Water samples
Fully automated determination of parabens, triclosan and methyl triclosan in wastewater by microextraction by packed sorbents and gas chromatography–mass spectrometry by Iria González-Mariño; José Benito Quintana; Isaac Rodríguez; Steffi Schrader; Monika Moeder (pp. 59-66).
A fully automated method for the determination of triclosan (TCS), its derivative methyl triclosan (MeTCS) and six parabens (esters of 4-hydroxybenzoic acid) including branched and linear isomers of propyl ( i-PrP and n-PrP) and butyl paraben ( i-BuP and n-BuP) in sewage water samples is presented. The procedure includes analytes enrichment by microextraction by packed sorbent (MEPS) coupled at-line to large volume injection-gas chromatography–mass spectrometry (LVI-GC–MS). Under optimised conditions, compounds were extracted from 2mL samples, adjusted at pH 3, using a C18 MEPS-sorbent. Adsorbed analytes were eluted directly into the Programmable Temperature Vaporizer (PTV) injector of the chromatograph with 2×25μL of ethyl acetate. They were quantified using standard solutions in ultrapure water submitted to the same sample enrichment process as real sewage water samples. After signal normalisation using isotopic labelled species as internal surrogates, no differences were noticed among the extraction efficiency for sewage and ultrapure water; moreover, the proposed method reported lineal calibration curves from 0.1 to 10ngmL−1, relative standard deviations (%RSD) between 2 and 7.1% and limits of detection (LODs) varying from 0.001 to 0.015ngmL−1 in ultrapure water and from 0.02 to 0.59ngmL−1 in the most complex sample (raw wastewater).
Keywords: Biocides; Extraction techniques; Microextraction; Automation; Gas chromatography–mass spectrometry; Water analysis
Synthesis and evaluation of tetracycline imprinted xerogels: Comparison of experiment and computational modeling by Elmer-Rico E. Mojica; Jochen Autschbach; Frank V. Bright; Diana S. Aga (pp. 63-71).
A series of silica-based tetracycline (TC)-imprinted xerogel sorbents were prepared by sol–gel processing and were characterized for TC binding. Molecularly imprinted xerogels (MIXs) formed from allyltriethoxysilane (AtEOS) and tetraethoxysilane (TEOS) and end capped with trimethylchlorosilane exhibited the best analytical performance (imprinting factor, IF, of 7.46±0.13). Computational modeling was used to estimate the interaction energy (IE) between TC and each type of silane to evaluate our ability to predict the analytical performance of a given MIX. Rankings from the computations agreed with the experimental data showing the AtEOS having the highest IE in comparison to the other formulations. Together, these results demonstrate the potential and limitations of using theoretical calculations to guide the development of analyte selective MIXs in comparison to arbitrary trial and error approaches traditionally used to produce MIXs as sorbents for solid phase extraction.
Keywords: Tetracycline; Molecular imprinting; Xerogel; Computational modeling; Solid phase extraction; Hartree-Fock calculations
Synthesis and evaluation of tetracycline imprinted xerogels: Comparison of experiment and computational modeling by Elmer-Rico E. Mojica; Jochen Autschbach; Frank V. Bright; Diana S. Aga (pp. 63-71).
A series of silica-based tetracycline (TC)-imprinted xerogel sorbents were prepared by sol–gel processing and were characterized for TC binding. Molecularly imprinted xerogels (MIXs) formed from allyltriethoxysilane (AtEOS) and tetraethoxysilane (TEOS) and end capped with trimethylchlorosilane exhibited the best analytical performance (imprinting factor, IF, of 7.46±0.13). Computational modeling was used to estimate the interaction energy (IE) between TC and each type of silane to evaluate our ability to predict the analytical performance of a given MIX. Rankings from the computations agreed with the experimental data showing the AtEOS having the highest IE in comparison to the other formulations. Together, these results demonstrate the potential and limitations of using theoretical calculations to guide the development of analyte selective MIXs in comparison to arbitrary trial and error approaches traditionally used to produce MIXs as sorbents for solid phase extraction.
Keywords: Tetracycline; Molecular imprinting; Xerogel; Computational modeling; Solid phase extraction; Hartree-Fock calculations
Headspace-solid phase microextraction of selenium(IV) from human blood and water samples using polypyrrole film and analysis with ion mobility spectrometry by Parvin Shahdousti; Naader Alizadeh (pp. 67-71).
Headspace-solid phase microextraction (HS-SPME) with a polypyrrole (PPy)-coated fiber was applied as a sample preparation method for determination of selenite [Se(IV)] following derivatization with 1,2-diaminobenzene to convert into the piaselenol form and analysis by ion mobility spectrometry (IMS). The HS-SPME–IMS method presents good repeatability (RSDs <6%), simplicity, good sensitivity and short analysis times. The influence of the various analytical parameters on microextraction procedure, i.e. ligand concentration, pH, ionic strength, equilibrium time and temperature has been evaluated and optimized. The calibration graph was linear in the range of 20–320ngmL−1 with a detection limit of 12ngmL−1. The method was applied for determination of selenium in human serum and environmental surface water samples with satisfactory recovery.
Keywords: Selenium; Headspace-solid phase microextraction; Polypyrrole; Ion mobility spectrometry; Human serum; Water samples
Collection of in vivo-like liver cell secretome with alternative sample enrichment method using a hollow fiber bioreactor culture system combined with tangential flow filtration for secretomics analysis by Yao-Tseng Wen; Yu-Chen Chang; Lung-Cheng Lin; Pao-Chi Liao (pp. 72-79).
A hollow fiber bioreactor (HFB) culture system coupled with a tangential flow filtration (TFF) device was used for HepG2 cell secretome analysis. In order to reduce the loss of low-molecular-weight proteins, two new features, the hollow fiber with 0.1μm pore size and a TFF device with a membrane of 1kDa molecular weight cutoff, were added to the system described previously. The HFB culture system and the conventional dish culture method for secretome collection were compared side by side. It was observed that only a small fraction of cells (<0.01%) were lysed in the HFB culture system, in contrast to the 2.73% in the conventional dish culture. A total of 111 proteins were identified in the collected conditioned medium (CM) by liquid chromatography–tandem mass spectrometry (LC–MS/MS) with this improved collection procedure. Many of these proteins reported to be biomarkers for liver-related diseases. About 16% of the identified proteins were smaller than 20kDa, demonstrating that the modified collection system had the ability to reduce the loss of low-molecular-weight proteins, in contrast to our previous collection system. The percentage increase of proteins classified as extracellular space or plasma membrane between the conventional dish culture and the HFB culture system was 40–60%. We believed that in vivo-like culture environments could support liver cells to improve protein secretion than conventional dish cultures. We suggest that the combination of the HFB culture system, TFF device, and LC–MS/MS analysis, would be an efficient procedure for the collection and characterization of in vivo-like cell secretome.
Keywords: Abbreviations; CM; conditioned medium; GPC3; glypican-3; HCC; hepatocellular carcinoma; HFB; hollow fiber bioreactor; HPRD; human protein reference database; LDH; lactate dehydrogenase; TFF; tangential flow filtrationHepG2; Hollow fiber bioreactor; LC–MS/MS; Proteome; Secretome
Collection of in vivo-like liver cell secretome with alternative sample enrichment method using a hollow fiber bioreactor culture system combined with tangential flow filtration for secretomics analysis by Yao-Tseng Wen; Yu-Chen Chang; Lung-Cheng Lin; Pao-Chi Liao (pp. 72-79).
A hollow fiber bioreactor (HFB) culture system coupled with a tangential flow filtration (TFF) device was used for HepG2 cell secretome analysis. In order to reduce the loss of low-molecular-weight proteins, two new features, the hollow fiber with 0.1μm pore size and a TFF device with a membrane of 1kDa molecular weight cutoff, were added to the system described previously. The HFB culture system and the conventional dish culture method for secretome collection were compared side by side. It was observed that only a small fraction of cells (<0.01%) were lysed in the HFB culture system, in contrast to the 2.73% in the conventional dish culture. A total of 111 proteins were identified in the collected conditioned medium (CM) by liquid chromatography–tandem mass spectrometry (LC–MS/MS) with this improved collection procedure. Many of these proteins reported to be biomarkers for liver-related diseases. About 16% of the identified proteins were smaller than 20kDa, demonstrating that the modified collection system had the ability to reduce the loss of low-molecular-weight proteins, in contrast to our previous collection system. The percentage increase of proteins classified as extracellular space or plasma membrane between the conventional dish culture and the HFB culture system was 40–60%. We believed that in vivo-like culture environments could support liver cells to improve protein secretion than conventional dish cultures. We suggest that the combination of the HFB culture system, TFF device, and LC–MS/MS analysis, would be an efficient procedure for the collection and characterization of in vivo-like cell secretome.
Keywords: Abbreviations; CM; conditioned medium; GPC3; glypican-3; HCC; hepatocellular carcinoma; HFB; hollow fiber bioreactor; HPRD; human protein reference database; LDH; lactate dehydrogenase; TFF; tangential flow filtrationHepG2; Hollow fiber bioreactor; LC–MS/MS; Proteome; Secretome
Synthesis and evaluation of tetracycline imprinted xerogels: Comparison of experiment and computational modeling by Elmer-Rico E. Mojica; Jochen Autschbach; Frank V. Bright; Diana S. Aga (pp. 72-80).
A series of silica-based tetracycline (TC)-imprinted xerogel sorbents were prepared by sol–gel processing and were characterized for TC binding. Molecularly imprinted xerogels (MIXs) formed from allyltriethoxysilane (AtEOS) and tetraethoxysilane (TEOS) and end capped with trimethylchlorosilane exhibited the best analytical performance (imprinting factor, IF, of 7.46±0.13). Computational modeling was used to estimate the interaction energy (IE) between TC and each type of silane to evaluate our ability to predict the analytical performance of a given MIX. Rankings from the computations agreed with the experimental data showing the AtEOS having the highest IE in comparison to the other formulations. Together, these results demonstrate the potential and limitations of using theoretical calculations to guide the development of analyte selective MIXs in comparison to arbitrary trial and error approaches traditionally used to produce MIXs as sorbents for solid phase extraction.
Keywords: Tetracycline; Molecular imprinting; Xerogel; Computational modeling; Solid phase extraction; Hartree-Fock calculations
Modification of major plasma proteins by acrylamide and glycidamide: Preliminary screening by nano liquid chromatography with tandem mass spectrometry by Chia-Hsien Feng; Chi-Yu Lu (pp. 80-86).
Environmental and food-borne acrylamide is a suspected carcinogen in humans and is associated with several cancer types. Its biological metabolite, glycidamide, is also harmful to human health. The presence of acrylamide in the living environment makes this toxic chemical an important public health issue. Acrylamide and glycidamide bind with proteins to form protein adducts in metabolic processes. These metabolic adducts can be considered environmental modifications of proteins. This study used a simple proteomic strategy to identify acrylamide and glycidamide adducts bound in major plasma proteins. After simple sample preparation, new protein modifications by acrylamide and glycidamide were identified using nano LC combined with quadruple time-of-flight (Q-TOF) mass spectrometry. This method required only 10μL of human plasma sample for protein modification survey. Hopefully, this strategy can help to discover protein–acrylamide (or glycidamide) adducts that are biomarkers of human exposure to high-dose acrylamide. These biomarkers may also elucidate the metabolic pathways of acrylamide and glycidamide.
Keywords: Acrylamide; Carcinogen; Glycidamide; Metabolite; Adducts; Biomarkers
Modification of major plasma proteins by acrylamide and glycidamide: Preliminary screening by nano liquid chromatography with tandem mass spectrometry by Chia-Hsien Feng; Chi-Yu Lu (pp. 80-86).
Environmental and food-borne acrylamide is a suspected carcinogen in humans and is associated with several cancer types. Its biological metabolite, glycidamide, is also harmful to human health. The presence of acrylamide in the living environment makes this toxic chemical an important public health issue. Acrylamide and glycidamide bind with proteins to form protein adducts in metabolic processes. These metabolic adducts can be considered environmental modifications of proteins. This study used a simple proteomic strategy to identify acrylamide and glycidamide adducts bound in major plasma proteins. After simple sample preparation, new protein modifications by acrylamide and glycidamide were identified using nano LC combined with quadruple time-of-flight (Q-TOF) mass spectrometry. This method required only 10μL of human plasma sample for protein modification survey. Hopefully, this strategy can help to discover protein–acrylamide (or glycidamide) adducts that are biomarkers of human exposure to high-dose acrylamide. These biomarkers may also elucidate the metabolic pathways of acrylamide and glycidamide.
Keywords: Acrylamide; Carcinogen; Glycidamide; Metabolite; Adducts; Biomarkers
Collection of in vivo-like liver cell secretome with alternative sample enrichment method using a hollow fiber bioreactor culture system combined with tangential flow filtration for secretomics analysis by Yao-Tseng Wen; Yu-Chen Chang; Lung-Cheng Lin; Pao-Chi Liao (pp. 81-88).
A hollow fiber bioreactor (HFB) culture system coupled with a tangential flow filtration (TFF) device was used for HepG2 cell secretome analysis. In order to reduce the loss of low-molecular-weight proteins, two new features, the hollow fiber with 0.1μm pore size and a TFF device with a membrane of 1kDa molecular weight cutoff, were added to the system described previously. The HFB culture system and the conventional dish culture method for secretome collection were compared side by side. It was observed that only a small fraction of cells (<0.01%) were lysed in the HFB culture system, in contrast to the 2.73% in the conventional dish culture. A total of 111 proteins were identified in the collected conditioned medium (CM) by liquid chromatography–tandem mass spectrometry (LC–MS/MS) with this improved collection procedure. Many of these proteins reported to be biomarkers for liver-related diseases. About 16% of the identified proteins were smaller than 20kDa, demonstrating that the modified collection system had the ability to reduce the loss of low-molecular-weight proteins, in contrast to our previous collection system. The percentage increase of proteins classified as extracellular space or plasma membrane between the conventional dish culture and the HFB culture system was 40–60%. We believed that in vivo-like culture environments could support liver cells to improve protein secretion than conventional dish cultures. We suggest that the combination of the HFB culture system, TFF device, and LC–MS/MS analysis, would be an efficient procedure for the collection and characterization of in vivo-like cell secretome.
Keywords: Abbreviations; CM; conditioned medium; GPC3; glypican-3; HCC; hepatocellular carcinoma; HFB; hollow fiber bioreactor; HPRD; human protein reference database; LDH; lactate dehydrogenase; TFF; tangential flow filtrationHepG2; Hollow fiber bioreactor; LC–MS/MS; Proteome; Secretome
Rapid wide-scope screening of drugs of abuse, prescription drugs with potential for abuse and their metabolites in influent and effluent urban wastewater by ultrahigh pressure liquid chromatography–quadrupole-time-of-flight-mass spectrometry by Félix Hernández; Lubertus Bijlsma; Juan V. Sancho; Ramon Díaz; María Ibáñez (pp. 87-97).
This work illustrates the potential of hybrid quadrupole-time-of-flight mass spectrometry (QTOF MS) coupled to ultrahigh pressure liquid chromatography (UHPLC) to investigate the presence of drugs of abuse in wastewater. After solid-phase extraction with Oasis MCX cartridges, seventy-six illicit drugs, prescription drugs with potential for abuse, and metabolites were investigated in the samples by TOF MS using electrospray interface under positive ionization mode, with MS data acquired over an m/ z range of 50–1000Da. For 11 compounds, reference standards were available, and experimental data (e.g., retention time and fragmentation data) could be obtained, facilitating a more confident identification. The use of a QTOF instrument enabled the simultaneous application of two acquisition functions with different collision energies: a low energy (LE) function, where none or poor fragmentation took place, and a high energy (HE) function, where fragmentation in the collision cell was promoted. This approach, known as MSE, enabled the simultaneous acquisition of full-spectrum accurate mass data of both protonated molecules and fragment ions in a single injection, providing relevant information that facilitates the rapid detection and reliable identification of these emerging contaminants in the sample matrices analyzed. In addition, isomeric compounds, like the opiates, morphine and norcodeine, could be discriminated by their specific fragments observed in HE TOF MS spectra, without the need of reference standards. UHPLC–QTOF MS was proven to be a powerful and efficient technique for rapid wide-scope screening and identification of many relevant drugs in complex matrices, such as influent and effluent urban wastewater.
Keywords: Illicit drugs of abuse; Ultrahigh pressure liquid chromatography; Time-of-flight mass spectrometry; MS; E; Wide-scope screening; Urban wastewater
Rapid wide-scope screening of drugs of abuse, prescription drugs with potential for abuse and their metabolites in influent and effluent urban wastewater by ultrahigh pressure liquid chromatography–quadrupole-time-of-flight-mass spectrometry by Félix Hernández; Lubertus Bijlsma; Juan V. Sancho; Ramon Díaz; María Ibáñez (pp. 87-97).
This work illustrates the potential of hybrid quadrupole-time-of-flight mass spectrometry (QTOF MS) coupled to ultrahigh pressure liquid chromatography (UHPLC) to investigate the presence of drugs of abuse in wastewater. After solid-phase extraction with Oasis MCX cartridges, seventy-six illicit drugs, prescription drugs with potential for abuse, and metabolites were investigated in the samples by TOF MS using electrospray interface under positive ionization mode, with MS data acquired over an m/ z range of 50–1000Da. For 11 compounds, reference standards were available, and experimental data (e.g., retention time and fragmentation data) could be obtained, facilitating a more confident identification. The use of a QTOF instrument enabled the simultaneous application of two acquisition functions with different collision energies: a low energy (LE) function, where none or poor fragmentation took place, and a high energy (HE) function, where fragmentation in the collision cell was promoted. This approach, known as MSE, enabled the simultaneous acquisition of full-spectrum accurate mass data of both protonated molecules and fragment ions in a single injection, providing relevant information that facilitates the rapid detection and reliable identification of these emerging contaminants in the sample matrices analyzed. In addition, isomeric compounds, like the opiates, morphine and norcodeine, could be discriminated by their specific fragments observed in HE TOF MS spectra, without the need of reference standards. UHPLC–QTOF MS was proven to be a powerful and efficient technique for rapid wide-scope screening and identification of many relevant drugs in complex matrices, such as influent and effluent urban wastewater.
Keywords: Illicit drugs of abuse; Ultrahigh pressure liquid chromatography; Time-of-flight mass spectrometry; MS; E; Wide-scope screening; Urban wastewater
Modification of major plasma proteins by acrylamide and glycidamide: Preliminary screening by nano liquid chromatography with tandem mass spectrometry by Chia-Hsien Feng; Chi-Yu Lu (pp. 89-95).
Environmental and food-borne acrylamide is a suspected carcinogen in humans and is associated with several cancer types. Its biological metabolite, glycidamide, is also harmful to human health. The presence of acrylamide in the living environment makes this toxic chemical an important public health issue. Acrylamide and glycidamide bind with proteins to form protein adducts in metabolic processes. These metabolic adducts can be considered environmental modifications of proteins. This study used a simple proteomic strategy to identify acrylamide and glycidamide adducts bound in major plasma proteins. After simple sample preparation, new protein modifications by acrylamide and glycidamide were identified using nano LC combined with quadruple time-of-flight (Q-TOF) mass spectrometry. This method required only 10μL of human plasma sample for protein modification survey. Hopefully, this strategy can help to discover protein–acrylamide (or glycidamide) adducts that are biomarkers of human exposure to high-dose acrylamide. These biomarkers may also elucidate the metabolic pathways of acrylamide and glycidamide.
Keywords: Acrylamide; Carcinogen; Glycidamide; Metabolite; Adducts; Biomarkers
Rapid wide-scope screening of drugs of abuse, prescription drugs with potential for abuse and their metabolites in influent and effluent urban wastewater by ultrahigh pressure liquid chromatography–quadrupole-time-of-flight-mass spectrometry by Félix Hernández; Lubertus Bijlsma; Juan V. Sancho; Ramon Díaz; María Ibáñez (pp. 96-106).
This work illustrates the potential of hybrid quadrupole-time-of-flight mass spectrometry (QTOF MS) coupled to ultrahigh pressure liquid chromatography (UHPLC) to investigate the presence of drugs of abuse in wastewater. After solid-phase extraction with Oasis MCX cartridges, seventy-six illicit drugs, prescription drugs with potential for abuse, and metabolites were investigated in the samples by TOF MS using electrospray interface under positive ionization mode, with MS data acquired over an m/ z range of 50–1000Da. For 11 compounds, reference standards were available, and experimental data (e.g., retention time and fragmentation data) could be obtained, facilitating a more confident identification. The use of a QTOF instrument enabled the simultaneous application of two acquisition functions with different collision energies: a low energy (LE) function, where none or poor fragmentation took place, and a high energy (HE) function, where fragmentation in the collision cell was promoted. This approach, known as MSE, enabled the simultaneous acquisition of full-spectrum accurate mass data of both protonated molecules and fragment ions in a single injection, providing relevant information that facilitates the rapid detection and reliable identification of these emerging contaminants in the sample matrices analyzed. In addition, isomeric compounds, like the opiates, morphine and norcodeine, could be discriminated by their specific fragments observed in HE TOF MS spectra, without the need of reference standards. UHPLC–QTOF MS was proven to be a powerful and efficient technique for rapid wide-scope screening and identification of many relevant drugs in complex matrices, such as influent and effluent urban wastewater.
Keywords: Illicit drugs of abuse; Ultrahigh pressure liquid chromatography; Time-of-flight mass spectrometry; MS; E; Wide-scope screening; Urban wastewater
Comparison between triple quadrupole, time of flight and hybrid quadrupole time of flight analysers coupled to liquid chromatography for the detection of anabolic steroids in doping control analysis by Oscar J. Pozo; Peter Van Eenoo; Koen Deventer; Hisham Elbardissy; Susana Grimalt; Juan V. Sancho; Felix Hernandez; Rosa Ventura; Frans T. Delbeke (pp. 98-111).
Triple quadrupole (QqQ), time of flight (TOF) and quadrupole-time of flight (QTOF) analysers have been compared for the detection of anabolic steroids in human urine. Ten anabolic steroids were selected as model compounds based on their ionization and the presence of endogenous interferences. Both qualitative and quantitative analyses were evaluated. QqQ allowed for the detection of all analytes at the minimum required performance limit (MRPL) established by the World Anti-Doping Agency (between 2 and 10ngmL−1 in urine). TOF and QTOF approaches were not sensitive enough to detect some of the analytes (3′-hydroxy-stanozolol or the metabolites of boldenone and formebolone) at the established MRPL. Although a suitable accuracy was obtained, the precision was unsatisfactory (RSD typically higher than 20%) for quantitative purposes irrespective of the analyser used. The methods were applied to 30 real samples declared positives either for the misuse of boldenone, stanozolol and/or methandienone. Most of the compounds were detected by every technique, however QqQ was necessary for the detection of some metabolites in a few samples. Finally, the possibility to detect non-target steroids has been explored by the use of TOF and QTOF. The use of this approach revealed that the presence of boldenone and its metabolite in one sample was due to the intake of androsta-1,4,6-triene-3,17-dione. Additionally, the intake of methandienone was confirmed by the post-target detection of a long-term metabolite.
Keywords: Anabolic steroids; Screening; Doping analysis; Mass spectrometry; Triple quadrupole; Time of flight; Hybrid quadrupole-time of flight
Comparison between triple quadrupole, time of flight and hybrid quadrupole time of flight analysers coupled to liquid chromatography for the detection of anabolic steroids in doping control analysis by Oscar J. Pozo; Peter Van Eenoo; Koen Deventer; Hisham Elbardissy; Susana Grimalt; Juan V. Sancho; Felix Hernandez; Rosa Ventura; Frans T. Delbeke (pp. 98-111).
Triple quadrupole (QqQ), time of flight (TOF) and quadrupole-time of flight (QTOF) analysers have been compared for the detection of anabolic steroids in human urine. Ten anabolic steroids were selected as model compounds based on their ionization and the presence of endogenous interferences. Both qualitative and quantitative analyses were evaluated. QqQ allowed for the detection of all analytes at the minimum required performance limit (MRPL) established by the World Anti-Doping Agency (between 2 and 10ngmL−1 in urine). TOF and QTOF approaches were not sensitive enough to detect some of the analytes (3′-hydroxy-stanozolol or the metabolites of boldenone and formebolone) at the established MRPL. Although a suitable accuracy was obtained, the precision was unsatisfactory (RSD typically higher than 20%) for quantitative purposes irrespective of the analyser used. The methods were applied to 30 real samples declared positives either for the misuse of boldenone, stanozolol and/or methandienone. Most of the compounds were detected by every technique, however QqQ was necessary for the detection of some metabolites in a few samples. Finally, the possibility to detect non-target steroids has been explored by the use of TOF and QTOF. The use of this approach revealed that the presence of boldenone and its metabolite in one sample was due to the intake of androsta-1,4,6-triene-3,17-dione. Additionally, the intake of methandienone was confirmed by the post-target detection of a long-term metabolite.
Keywords: Anabolic steroids; Screening; Doping analysis; Mass spectrometry; Triple quadrupole; Time of flight; Hybrid quadrupole-time of flight
Comparison between triple quadrupole, time of flight and hybrid quadrupole time of flight analysers coupled to liquid chromatography for the detection of anabolic steroids in doping control analysis by Oscar J. Pozo; Peter Van Eenoo; Koen Deventer; Hisham Elbardissy; Susana Grimalt; Juan V. Sancho; Felix Hernandez; Rosa Ventura; Frans T. Delbeke (pp. 107-120).
Triple quadrupole (QqQ), time of flight (TOF) and quadrupole-time of flight (QTOF) analysers have been compared for the detection of anabolic steroids in human urine. Ten anabolic steroids were selected as model compounds based on their ionization and the presence of endogenous interferences. Both qualitative and quantitative analyses were evaluated. QqQ allowed for the detection of all analytes at the minimum required performance limit (MRPL) established by the World Anti-Doping Agency (between 2 and 10ngmL−1 in urine). TOF and QTOF approaches were not sensitive enough to detect some of the analytes (3′-hydroxy-stanozolol or the metabolites of boldenone and formebolone) at the established MRPL. Although a suitable accuracy was obtained, the precision was unsatisfactory (RSD typically higher than 20%) for quantitative purposes irrespective of the analyser used. The methods were applied to 30 real samples declared positives either for the misuse of boldenone, stanozolol and/or methandienone. Most of the compounds were detected by every technique, however QqQ was necessary for the detection of some metabolites in a few samples. Finally, the possibility to detect non-target steroids has been explored by the use of TOF and QTOF. The use of this approach revealed that the presence of boldenone and its metabolite in one sample was due to the intake of androsta-1,4,6-triene-3,17-dione. Additionally, the intake of methandienone was confirmed by the post-target detection of a long-term metabolite.
Keywords: Anabolic steroids; Screening; Doping analysis; Mass spectrometry; Triple quadrupole; Time of flight; Hybrid quadrupole-time of flight
Typing of unknown microorganisms based on quantitative analysis of fatty acids by mass spectrometry and hierarchical clustering by Tingting Li; Ling Dai; Lun Li; Xuejiao Hu; Linjie Dong; Jianjian Li; Sule Khalfan Salim; Jieying Fu; Hongying Zhong (pp. 112-120).
Rapid identification of unknown microorganisms of clinical and agricultural importance is not only critical for accurate diagnosis of infections but also essential for appropriate and prompt treatment. We describe here a rapid method for microorganisms typing based on quantitative analysis of fatty acids by iFAT approach (Isotope-coded Fatty Acid Transmethylation). In this work, lyophilized cell lysates were directly mixed with 0.5M NaOH solution in d3-methanol and n-hexane. After 1min of ultrasonication, the top n-hexane layer was combined with a mixture of standard d0-methanol derived fatty acid methylesters with known concentration. Measurement of intensity ratios of d3/d0 labeled fragment ion and molecular ion pairs at the corresponding target fatty acids provides a quantitative basis for hierarchical clustering. In the resultant dendrogram, the Euclidean distance between unknown species and known species quantitatively reveals their differences or shared similarities in fatty acid related pathways. It is of particular interest to apply this method for typing fungal species because fungi has distinguished lipid biosynthetic pathways that have been targeted for lots of drugs or fungicides compared with bacteria and animals. The proposed method has no dependence on the availability of genome or proteome databases. Therefore, it is can be applicable for a broad range of unknown microorganisms or mutant species.
Keywords: Microorganism identification; Fatty acids; Hierarchical clustering; Mass spectrometry; Stable isotope labeling
Typing of unknown microorganisms based on quantitative analysis of fatty acids by mass spectrometry and hierarchical clustering by Tingting Li; Ling Dai; Lun Li; Xuejiao Hu; Linjie Dong; Jianjian Li; Sule Khalfan Salim; Jieying Fu; Hongying Zhong (pp. 112-120).
Rapid identification of unknown microorganisms of clinical and agricultural importance is not only critical for accurate diagnosis of infections but also essential for appropriate and prompt treatment. We describe here a rapid method for microorganisms typing based on quantitative analysis of fatty acids by iFAT approach (Isotope-coded Fatty Acid Transmethylation). In this work, lyophilized cell lysates were directly mixed with 0.5M NaOH solution in d3-methanol and n-hexane. After 1min of ultrasonication, the top n-hexane layer was combined with a mixture of standard d0-methanol derived fatty acid methylesters with known concentration. Measurement of intensity ratios of d3/d0 labeled fragment ion and molecular ion pairs at the corresponding target fatty acids provides a quantitative basis for hierarchical clustering. In the resultant dendrogram, the Euclidean distance between unknown species and known species quantitatively reveals their differences or shared similarities in fatty acid related pathways. It is of particular interest to apply this method for typing fungal species because fungi has distinguished lipid biosynthetic pathways that have been targeted for lots of drugs or fungicides compared with bacteria and animals. The proposed method has no dependence on the availability of genome or proteome databases. Therefore, it is can be applicable for a broad range of unknown microorganisms or mutant species.
Keywords: Microorganism identification; Fatty acids; Hierarchical clustering; Mass spectrometry; Stable isotope labeling
Highly sensitive electrochemiluminescent biosensor for adenosine based on structure-switching of aptamer by Xi Zhu; Yashan Zhang; Weiqiang Yang; Qida Liu; Zhenyu Lin; Bin Qiu; Guonan Chen (pp. 121-125).
A highly sensitive and selective electrochemiluminescent (ECL) biosensor for the determination of adenosine was developed. Single DNA (capture DNA) was immobilized on the gold electrode through Au–thiol interaction at first. Another DNA modified with tris(2,2′-bipyridyl) ruthenium(II)-doped silica nanoparticles (Ru-SNPs) that contained adenosine aptamer was then modified on the electrode surface through hybridizing with the capture DNA. In the presence of adenosine, adenosine–aptamer complex is produced rather than aptamer–DNA duplex, resulting with the dissociation of Ru-SNPs-labeled aptamer from the electrode surface and the decrease in the ECL intensity. The decrease of ECL intensity has a direct relationship with the logarithm of adenosine concentration in the range of 1.0×10−10 to 5.0×10−6molL−1. The detection limit of the proposed method is 3.0×10−11molL−1. The existence of guanosine, cytidine and uridine has little interference with adenosine detection, demonstrating that the developed biosensor owns a high selectivity to adenosine. In addition, the developed biosensor also demonstrates very good reusability, as after being reused for 30 times, its ECL signal still keeps 91% of its original state.
Keywords: Aptamer; Adenosine; Electrochemiluminescent biosensor; Ru(bpy); 3; 2+; -doped silica nanoparticles
Highly sensitive electrochemiluminescent biosensor for adenosine based on structure-switching of aptamer by Xi Zhu; Yashan Zhang; Weiqiang Yang; Qida Liu; Zhenyu Lin; Bin Qiu; Guonan Chen (pp. 121-125).
A highly sensitive and selective electrochemiluminescent (ECL) biosensor for the determination of adenosine was developed. Single DNA (capture DNA) was immobilized on the gold electrode through Au–thiol interaction at first. Another DNA modified with tris(2,2′-bipyridyl) ruthenium(II)-doped silica nanoparticles (Ru-SNPs) that contained adenosine aptamer was then modified on the electrode surface through hybridizing with the capture DNA. In the presence of adenosine, adenosine–aptamer complex is produced rather than aptamer–DNA duplex, resulting with the dissociation of Ru-SNPs-labeled aptamer from the electrode surface and the decrease in the ECL intensity. The decrease of ECL intensity has a direct relationship with the logarithm of adenosine concentration in the range of 1.0×10−10 to 5.0×10−6molL−1. The detection limit of the proposed method is 3.0×10−11molL−1. The existence of guanosine, cytidine and uridine has little interference with adenosine detection, demonstrating that the developed biosensor owns a high selectivity to adenosine. In addition, the developed biosensor also demonstrates very good reusability, as after being reused for 30 times, its ECL signal still keeps 91% of its original state.
Keywords: Aptamer; Adenosine; Electrochemiluminescent biosensor; Ru(bpy); 3; 2+; -doped silica nanoparticles
Highly sensitive electrochemiluminescent biosensor for adenosine based on structure-switching of aptamer by Xi Zhu; Yashan Zhang; Weiqiang Yang; Qida Liu; Zhenyu Lin; Bin Qiu; Guonan Chen (pp. 121-125).
A highly sensitive and selective electrochemiluminescent (ECL) biosensor for the determination of adenosine was developed. Single DNA (capture DNA) was immobilized on the gold electrode through Au–thiol interaction at first. Another DNA modified with tris(2,2′-bipyridyl) ruthenium(II)-doped silica nanoparticles (Ru-SNPs) that contained adenosine aptamer was then modified on the electrode surface through hybridizing with the capture DNA. In the presence of adenosine, adenosine–aptamer complex is produced rather than aptamer–DNA duplex, resulting with the dissociation of Ru-SNPs-labeled aptamer from the electrode surface and the decrease in the ECL intensity. The decrease of ECL intensity has a direct relationship with the logarithm of adenosine concentration in the range of 1.0×10−10 to 5.0×10−6molL−1. The detection limit of the proposed method is 3.0×10−11molL−1. The existence of guanosine, cytidine and uridine has little interference with adenosine detection, demonstrating that the developed biosensor owns a high selectivity to adenosine. In addition, the developed biosensor also demonstrates very good reusability, as after being reused for 30 times, its ECL signal still keeps 91% of its original state.
Keywords: Aptamer; Adenosine; Electrochemiluminescent biosensor; Ru(bpy); 3; 2+; -doped silica nanoparticles
Selenium speciation analysis at trace level in soils by Julie Tolu; Isabelle Le Hécho; Maïté Bueno; Yves Thiry; Martine Potin-Gautier (pp. 126-133).
This paper describes the development of an analytical methodology to determine speciation of selenium present in soils at trace level (μgkg−1). The methodology was based on parallel single extractions and high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC–ICPMS). Two complementary chromatographic separations were used to confirm Se species identity. Different extractants, selected on the basis of sequential extraction schemes, were compared. Ultrapure water, 0.1molL−1 phosphate buffer (KH2PO4/K2HPO4) at pH 7 and 0.1molL−1 sodium hydroxide extractants were finally chosen owing to their efficiency in extracting Se and compatibility with Se species stability. These extractants allow also assessing respectively water-soluble Se (i.e. the most mobile Se fraction), exchangeable Se (i.e. sorbed onto soil component surface) and Se bound to soil organic matter. This methodology gives thus information on Se mobility related to its distribution in soil with preservation of original Se speciation. Detection limits range from 3 to 29ng(Se)L−1 and from 0.1 to 10μg(Se)kg−1, allowing determination of Se species concentrations in extracts from soils containing native Se at trace level. The methodology was applied to three soils with total Se concentrations between 210 and 1560μg(Se)kg−1.
Keywords: Selenium speciation; Soil; Trace level; Single extractions; Hyphenated analytical technique
Selenium speciation analysis at trace level in soils by Julie Tolu; Isabelle Le Hécho; Maïté Bueno; Yves Thiry; Martine Potin-Gautier (pp. 126-133).
This paper describes the development of an analytical methodology to determine speciation of selenium present in soils at trace level (μgkg−1). The methodology was based on parallel single extractions and high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC–ICPMS). Two complementary chromatographic separations were used to confirm Se species identity. Different extractants, selected on the basis of sequential extraction schemes, were compared. Ultrapure water, 0.1molL−1 phosphate buffer (KH2PO4/K2HPO4) at pH 7 and 0.1molL−1 sodium hydroxide extractants were finally chosen owing to their efficiency in extracting Se and compatibility with Se species stability. These extractants allow also assessing respectively water-soluble Se (i.e. the most mobile Se fraction), exchangeable Se (i.e. sorbed onto soil component surface) and Se bound to soil organic matter. This methodology gives thus information on Se mobility related to its distribution in soil with preservation of original Se speciation. Detection limits range from 3 to 29ng(Se)L−1 and from 0.1 to 10μg(Se)kg−1, allowing determination of Se species concentrations in extracts from soils containing native Se at trace level. The methodology was applied to three soils with total Se concentrations between 210 and 1560μg(Se)kg−1.
Keywords: Selenium speciation; Soil; Trace level; Single extractions; Hyphenated analytical technique
Selenium speciation analysis at trace level in soils by Julie Tolu; Isabelle Le Hécho; Maïté Bueno; Yves Thiry; Martine Potin-Gautier (pp. 126-133).
This paper describes the development of an analytical methodology to determine speciation of selenium present in soils at trace level (μgkg−1). The methodology was based on parallel single extractions and high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC–ICPMS). Two complementary chromatographic separations were used to confirm Se species identity. Different extractants, selected on the basis of sequential extraction schemes, were compared. Ultrapure water, 0.1molL−1 phosphate buffer (KH2PO4/K2HPO4) at pH 7 and 0.1molL−1 sodium hydroxide extractants were finally chosen owing to their efficiency in extracting Se and compatibility with Se species stability. These extractants allow also assessing respectively water-soluble Se (i.e. the most mobile Se fraction), exchangeable Se (i.e. sorbed onto soil component surface) and Se bound to soil organic matter. This methodology gives thus information on Se mobility related to its distribution in soil with preservation of original Se speciation. Detection limits range from 3 to 29ng(Se)L−1 and from 0.1 to 10μg(Se)kg−1, allowing determination of Se species concentrations in extracts from soils containing native Se at trace level. The methodology was applied to three soils with total Se concentrations between 210 and 1560μg(Se)kg−1.
Keywords: Selenium speciation; Soil; Trace level; Single extractions; Hyphenated analytical technique
Screening for antioxidants in complex matrices using high performance liquid chromatography with acidic potassium permanganate chemiluminescence detection by Geoffrey P. McDermott; Xavier A. Conlan; Laura K. Noonan; Jason W. Costin; Mariam Mnatsakanyan; R. Andrew Shalliker; Neil W. Barnett; Paul S. Francis (pp. 134-141).
The use of high performance liquid chromatography with acidic potassium permanganate chemiluminescence detection to screen for antioxidants in complex plant-derived samples was evaluated in comparison with two conventional post-column radical scavenging assays (2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS+)). In this approach, acidic potassium permanganate can react with readily oxidisable compounds (potential antioxidants), post-column, to produce chemiluminescence. Using flow injection analysis, experimental parameters that afforded the most suitable permanganate chemiluminescence signal for a range of known antioxidants were studied in a univariate approach. Optimum conditions were found to be: 1×10−3M potassium permanganate solution containing 1% (w/v) sodium polyphosphates adjusted to pH 2 with sulphuric acid, delivered at a flow rate of 2.5mLmin−1 per line. Further investigations showed some differences in detection selectivity between HPLC with the optimised post-column permanganate chemiluminescence detection and DPPH and ABTS+ assays towards antioxidant standards. However, permanganate chemiluminescence detection was more sensitive. Moreover, screening for antioxidants in green tea, cranberry juice and thyme using potassium permanganate chemiluminescence offers several advantages over the traditional DPPH and ABTS+ assays, such as faster reagent preparation and superior stability; simpler post-column reaction manifold; and greater compatibility with fast chromatographic separations using monolithic columns.
Keywords: High performance liquid chromatography; Flow injection analysis; Acidic potassium permanganate chemiluminescence; 2,2-Diphenyl-1-picrylhydrazyl; 2,2′-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid); Green tea; Cranberry juice; Thyme
Screening for antioxidants in complex matrices using high performance liquid chromatography with acidic potassium permanganate chemiluminescence detection by Geoffrey P. McDermott; Xavier A. Conlan; Laura K. Noonan; Jason W. Costin; Mariam Mnatsakanyan; R. Andrew Shalliker; Neil W. Barnett; Paul S. Francis (pp. 134-141).
The use of high performance liquid chromatography with acidic potassium permanganate chemiluminescence detection to screen for antioxidants in complex plant-derived samples was evaluated in comparison with two conventional post-column radical scavenging assays (2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS+)). In this approach, acidic potassium permanganate can react with readily oxidisable compounds (potential antioxidants), post-column, to produce chemiluminescence. Using flow injection analysis, experimental parameters that afforded the most suitable permanganate chemiluminescence signal for a range of known antioxidants were studied in a univariate approach. Optimum conditions were found to be: 1×10−3M potassium permanganate solution containing 1% (w/v) sodium polyphosphates adjusted to pH 2 with sulphuric acid, delivered at a flow rate of 2.5mLmin−1 per line. Further investigations showed some differences in detection selectivity between HPLC with the optimised post-column permanganate chemiluminescence detection and DPPH and ABTS+ assays towards antioxidant standards. However, permanganate chemiluminescence detection was more sensitive. Moreover, screening for antioxidants in green tea, cranberry juice and thyme using potassium permanganate chemiluminescence offers several advantages over the traditional DPPH and ABTS+ assays, such as faster reagent preparation and superior stability; simpler post-column reaction manifold; and greater compatibility with fast chromatographic separations using monolithic columns.
Keywords: High performance liquid chromatography; Flow injection analysis; Acidic potassium permanganate chemiluminescence; 2,2-Diphenyl-1-picrylhydrazyl; 2,2′-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid); Green tea; Cranberry juice; Thyme
Screening for antioxidants in complex matrices using high performance liquid chromatography with acidic potassium permanganate chemiluminescence detection by Geoffrey P. McDermott; Xavier A. Conlan; Laura K. Noonan; Jason W. Costin; Mariam Mnatsakanyan; R. Andrew Shalliker; Neil W. Barnett; Paul S. Francis (pp. 134-141).
The use of high performance liquid chromatography with acidic potassium permanganate chemiluminescence detection to screen for antioxidants in complex plant-derived samples was evaluated in comparison with two conventional post-column radical scavenging assays (2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS+)). In this approach, acidic potassium permanganate can react with readily oxidisable compounds (potential antioxidants), post-column, to produce chemiluminescence. Using flow injection analysis, experimental parameters that afforded the most suitable permanganate chemiluminescence signal for a range of known antioxidants were studied in a univariate approach. Optimum conditions were found to be: 1×10−3M potassium permanganate solution containing 1% (w/v) sodium polyphosphates adjusted to pH 2 with sulphuric acid, delivered at a flow rate of 2.5mLmin−1 per line. Further investigations showed some differences in detection selectivity between HPLC with the optimised post-column permanganate chemiluminescence detection and DPPH and ABTS+ assays towards antioxidant standards. However, permanganate chemiluminescence detection was more sensitive. Moreover, screening for antioxidants in green tea, cranberry juice and thyme using potassium permanganate chemiluminescence offers several advantages over the traditional DPPH and ABTS+ assays, such as faster reagent preparation and superior stability; simpler post-column reaction manifold; and greater compatibility with fast chromatographic separations using monolithic columns.
Keywords: High performance liquid chromatography; Flow injection analysis; Acidic potassium permanganate chemiluminescence; 2,2-Diphenyl-1-picrylhydrazyl; 2,2′-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid); Green tea; Cranberry juice; Thyme
New resin gel for uranium determination by diffusive gradient in thin films technique by Michaela Gregusova; Bohumil Docekal (pp. 142-146).
A new resin gel based on Spheron-Oxin® chelating ion-exchanger with anchored 8-hydroxyquinoline functional groups was tested for application in diffusive gradient in thin film technique (DGT) for determination of uranium. Selectivity of uranium uptake from model carbonate loaded solutions of natural water was studied under laboratory conditions and compared with selectivity of the conventional Chelex 100 based resin gel. The affinity of Spheron-Oxin® functional groups enables determination of the overall uranium concentration in water containing carbonates up to the concentration level of 102mgL−1. The effect of uranium binding to the polyacrylamide (APA) and agarose diffusive gels (AGE) was also studied. Uranium is probably bound in both gels by a weak interaction with traces of acrylic acid groups in the structure of APA gel and with pyruvic and sulfonic acid groups in the AGE gel. These sorption effects can be eliminated to the negligible level by prolonged deployment of DGT probes or by disassembling probes after the 1–2 days post-sampling period that is sufficient for release of uranium from diffusive gel and its sorption in resin gel.
Keywords: Diffusive gradient in thin film technique; 8-Hydroxyquinoline resin gel; Uranium determination
New resin gel for uranium determination by diffusive gradient in thin films technique by Michaela Gregusova; Bohumil Docekal (pp. 142-146).
A new resin gel based on Spheron-Oxin® chelating ion-exchanger with anchored 8-hydroxyquinoline functional groups was tested for application in diffusive gradient in thin film technique (DGT) for determination of uranium. Selectivity of uranium uptake from model carbonate loaded solutions of natural water was studied under laboratory conditions and compared with selectivity of the conventional Chelex 100 based resin gel. The affinity of Spheron-Oxin® functional groups enables determination of the overall uranium concentration in water containing carbonates up to the concentration level of 102mgL−1. The effect of uranium binding to the polyacrylamide (APA) and agarose diffusive gels (AGE) was also studied. Uranium is probably bound in both gels by a weak interaction with traces of acrylic acid groups in the structure of APA gel and with pyruvic and sulfonic acid groups in the AGE gel. These sorption effects can be eliminated to the negligible level by prolonged deployment of DGT probes or by disassembling probes after the 1–2 days post-sampling period that is sufficient for release of uranium from diffusive gel and its sorption in resin gel.
Keywords: Diffusive gradient in thin film technique; 8-Hydroxyquinoline resin gel; Uranium determination
New resin gel for uranium determination by diffusive gradient in thin films technique by Michaela Gregusova; Bohumil Docekal (pp. 142-146).
A new resin gel based on Spheron-Oxin® chelating ion-exchanger with anchored 8-hydroxyquinoline functional groups was tested for application in diffusive gradient in thin film technique (DGT) for determination of uranium. Selectivity of uranium uptake from model carbonate loaded solutions of natural water was studied under laboratory conditions and compared with selectivity of the conventional Chelex 100 based resin gel. The affinity of Spheron-Oxin® functional groups enables determination of the overall uranium concentration in water containing carbonates up to the concentration level of 102mgL−1. The effect of uranium binding to the polyacrylamide (APA) and agarose diffusive gels (AGE) was also studied. Uranium is probably bound in both gels by a weak interaction with traces of acrylic acid groups in the structure of APA gel and with pyruvic and sulfonic acid groups in the AGE gel. These sorption effects can be eliminated to the negligible level by prolonged deployment of DGT probes or by disassembling probes after the 1–2 days post-sampling period that is sufficient for release of uranium from diffusive gel and its sorption in resin gel.
Keywords: Diffusive gradient in thin film technique; 8-Hydroxyquinoline resin gel; Uranium determination