The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Peter J Oefner - One of the best experts on this subject based on the ideXlab platform.
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urinary Amino Acid Analysis a comparison of itraq lc ms ms gc ms and Amino Acid analyzer
Journal of Chromatography B, 2009Co-Authors: Hannelore Kaspar, Katja Dettmer, Queenie Chan, Scott Daniels, Subodh B Nimkar, Martha L Daviglus, Jeremiah Stamler, Paul Elliott, Peter J OefnerAbstract:Urinary Amino Acid Analysis is typically done by cation-exchange chromatography followed by post-column derivatization with ninhydrin and UV detection. This method lacks throughput and specificity. Two recently introduced stable isotope ratio mass spectrometric methods promise to overcome those shortcomings. Using two blinded sets of urine replicates and a certified Amino Acid standard, we compared the precision and accuracy of gas chromatography/mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of propyl chloroformate and iTRAQ derivatized Amino Acids, respectively, to conventional Amino Acid Analysis. The GC-MS method builds on the direct derivatization of Amino Acids in diluted urine with propyl chloroformate, GC separation and mass spectrometric quantification of derivatives using stable isotope labeled standards. The LC-MS/MS method requires prior urinary protein precipitation followed by labeling of urinary and standard Amino Acids with iTRAQ tags containing different cleavable reporter ions distinguishable by MS/MS fragmentation. Means and standard deviations of percent technical error (%TE) computed for 20 Amino Acids determined by Amino Acid analyzer, GC-MS, and iTRAQ-LC-MS/MS analyses of 33 duplicate and triplicate urine specimens were 7.27+/-5.22, 21.18+/-10.94, and 18.34+/-14.67, respectively. Corresponding values for 13 Amino Acids determined in a second batch of 144 urine specimens measured in duplicate or triplicate were 8.39+/-5.35, 6.23+/-3.84, and 35.37+/-29.42. Both GC-MS and iTRAQ-LC-MS/MS are suited for high-throughput Amino Acid Analysis, with the former offering at present higher reproducibility and completely automated sample pretreatment, while the latter covers more Amino Acids and related amines.
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advances in Amino Acid Analysis
Analytical and Bioanalytical Chemistry, 2009Co-Authors: Hannelore Kaspar, Katja Dettmer, Wolfram Gronwald, Peter J OefnerAbstract:Amino Acids are important targets for metabolic profiling. For decades, Amino Acid Analysis has been accomplished by either cation-exchange or reversed-phase liquid chromatography coupled to UV absorbance or fluorescence detection of pre-column or post-column-derivatized Amino Acids. Recent years have seen great progress in the development of direct-infusion or hyphenated mass spectrometry in the Analysis of free Amino Acids in physiological fluids, because mass spectrometry not only matches optical detection in sensitivity, but also offers superior selectivity. The advent of cryo-probes has also brought NMR spectroscopy within the detection limits required for the Analysis of free Amino Acids. But there is still room for further improvement, including expansion of the analyte spectrum, reduction of sample preparation and Analysis time, automation, and synthesis of affordable isotope standards.
François Couderc - One of the best experts on this subject based on the ideXlab platform.
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Recent advances in Amino Acid Analysis by capillary electromigration methods: June 2015-May 2017
Electrophoresis, 2017Co-Authors: Véréna Poinsot, Pierre Gavard, Varravaddheay Ong-meang, Lucie Perquis, François CoudercAbstract:In the tenth edition of this article focused on recent advances in Amino Acid Analysis using capillary electrophoresis, we describe the most important research articles published on this topic during the period from June 2015 to May 2017. This article follows the format of the previous articles published in Electrophoresis. The new developments in Amino Acid Analysis with CE mainly describe improvements in CE associated with mass spectrometry. Focusing on applications, we mostly describe clinical works, although metabolomics studies are also very important. Finally, works focusing on Amino Acids in food and agricultural applications are also described.
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Recent advances in Amino Acid Analysis by capillary electrophoresis
Electrophoresis, 2012Co-Authors: Véréna Poinsot, Marie Anne Carpéné, Pierre Gavard, Bernard Feurer, Jalloul Bouajila, François CoudercAbstract:This paper describes a number of articles that have been published on Amino Acid Analysis using CE during the period from June 2003 to May 2005. This review article follows the previous ones of Smith (Electrophoresis 1999, 20, 3078-3083), Prata et al. (Electrophoresis 2001, 22, 4129-4138), and Poinsot et al. (Electrophoresis 2003, 24, 4047-4062). Several new developments in Amino Acid Analysis with CE are reported concerning UV detection, LIF, MS, and NMR. In addition, we describe articles concerning clinical and pharmaceutical studies, neuroclinical applications, and agricultural and food Analysis.
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Recent advances in Amino Acid Analysis by capillary electrophoresis.
Electrophoresis, 2011Co-Authors: Véréna Poinsot, Marie Anne Carpéné, Pierre Gavard, Bernard Feurer, Jalloul Bouajila, François CoudercAbstract:This paper describes the most important articles that have been published on Amino Acid Analysis using CE during the period from June 2009 to May 2011 and follows the format of the previous articles of Smith (Electrophoresis 1999, 20, 3078-3083), Prata et al. (Electrophoresis 2001, 22, 4129-4138) and Poinsot et al. (Electrophoresis 2003, 24, 4047-4062; Electrophoresis 2006, 27, 176-194; Electrophoresis 2008, 29, 207-223; Electrophoresis 2010, 31, 105-121). We present new developments in Amino Acid Analysis with CE, which are reported describing the use of lasers or light emitting diodes for fluorescence detection, conductimetry electrochemiluminescence detectors, mass spectrometry applications, and lab-on-a-chip applications using CE. In addition, we describe articles concerning clinical studies and neurochemical applications of these techniques.
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Recent advances in Amino Acid Analysis by CE
Electrophoresis, 2010Co-Authors: Véréna Poinsot, Pierre Gavard, Bernard Feurer, François CoudercAbstract:This article describes the most important articles that have been published on Amino Acid Analysis using CE during the period from June 2007 to May 2009. It follows the format of the previous articles of Smith [Electrophoresis 1999, 20, 3078-3083], Prata et al. [Electrophoresis 2001, 22, 4129-4138] and Poinsot et al. [Electrophoresis 2003, 24, 4047-4062; Electrophoresis 2006, 27, 176-194; Electrophoresis 2008, 29, 207-223]. For several years we have presented the new developments in Amino Acid Analysis with CE which describe the use of laser emitting diodes for LIF as well as via MS. In addition, we describe articles concerning clinical studies and neuroclinical applications.
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Recent advances in Amino Acid Analysis by capillary electrophoresis.
Electrophoresis, 2003Co-Authors: Véréna Poinsot, Christophe Bayle, François CoudercAbstract:Amino Acids are studied extensively using capillary electrophoresis. In a previous article, we reviewed applications reported in the period 1999-early 2001 (Prata, C., Bonnafous, P., Fraysse, N., Treilhou, M., Poinsot, V., Couderc, F., Electrophoresis 2001, 22, 4129-4138). In this article we follow on with this review for the period end of 2001-beginning of 2003. We will report the developments of detection methods, separations of enantiomers, the new medical applications, and Amino Acids in food and plants. This review shows that CE is more and more important for the Amino Acid Analysis.
Wei Du - One of the best experts on this subject based on the ideXlab platform.
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recent advances in microchip electrophoresis for Amino Acid Analysis
Analytical Abstracts, 2013Co-Authors: Gaozhi Ou, Xiaojun Feng, Wei DuAbstract:With the maturation of microfluidic technologies, microchip electrophoresis has been widely employed for Amino Acid Analysis owing to its advantages of low sample consumption, reduced Analysis time, high throughput, and potential for integration and automation. In this article, we review the recent progress in Amino Acid Analysis using microchip electrophoresis during the period from 2007 to 2012. Innovations in microchip materials, surface modification, sample introduction, microchip electrophoresis, and detection methods are documented, as well as nascent applications of Amino Acid Analysis in single-cell Analysis, microdialysis sampling, food Analysis, and extraterrestrial exploration. Without doubt, more applications of microchip electrophoresis in Amino Acid Analysis may be expected soon (review).
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recent advances in microchip electrophoresis for Amino Acid Analysis
Analytical and Bioanalytical Chemistry, 2013Co-Authors: Gaozhi Ou, Xiaojun Feng, Wei DuAbstract:With the maturation of microfluidic technologies, microchip electrophoresis has been widely employed for Amino Acid Analysis owing to its advantages of low sample consumption, reduced Analysis time, high throughput, and potential for integration and automation. In this article, we review the recent progress in Amino Acid Analysis using microchip electrophoresis during the period from 2007 to 2012. Innovations in microchip materials, surface modification, sample introduction, microchip electrophoresis, and detection methods are documented, as well as nascent applications of Amino Acid Analysis in single-cell Analysis, microdialysis sampling, food Analysis, and extraterrestrial exploration. Without doubt, more applications of microchip electrophoresis in Amino Acid Analysis may be expected soon.
Hannelore Kaspar - One of the best experts on this subject based on the ideXlab platform.
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urinary Amino Acid Analysis a comparison of itraq lc ms ms gc ms and Amino Acid analyzer
Journal of Chromatography B, 2009Co-Authors: Hannelore Kaspar, Katja Dettmer, Queenie Chan, Scott Daniels, Subodh B Nimkar, Martha L Daviglus, Jeremiah Stamler, Paul Elliott, Peter J OefnerAbstract:Urinary Amino Acid Analysis is typically done by cation-exchange chromatography followed by post-column derivatization with ninhydrin and UV detection. This method lacks throughput and specificity. Two recently introduced stable isotope ratio mass spectrometric methods promise to overcome those shortcomings. Using two blinded sets of urine replicates and a certified Amino Acid standard, we compared the precision and accuracy of gas chromatography/mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of propyl chloroformate and iTRAQ derivatized Amino Acids, respectively, to conventional Amino Acid Analysis. The GC-MS method builds on the direct derivatization of Amino Acids in diluted urine with propyl chloroformate, GC separation and mass spectrometric quantification of derivatives using stable isotope labeled standards. The LC-MS/MS method requires prior urinary protein precipitation followed by labeling of urinary and standard Amino Acids with iTRAQ tags containing different cleavable reporter ions distinguishable by MS/MS fragmentation. Means and standard deviations of percent technical error (%TE) computed for 20 Amino Acids determined by Amino Acid analyzer, GC-MS, and iTRAQ-LC-MS/MS analyses of 33 duplicate and triplicate urine specimens were 7.27+/-5.22, 21.18+/-10.94, and 18.34+/-14.67, respectively. Corresponding values for 13 Amino Acids determined in a second batch of 144 urine specimens measured in duplicate or triplicate were 8.39+/-5.35, 6.23+/-3.84, and 35.37+/-29.42. Both GC-MS and iTRAQ-LC-MS/MS are suited for high-throughput Amino Acid Analysis, with the former offering at present higher reproducibility and completely automated sample pretreatment, while the latter covers more Amino Acids and related amines.
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advances in Amino Acid Analysis
Analytical and Bioanalytical Chemistry, 2009Co-Authors: Hannelore Kaspar, Katja Dettmer, Wolfram Gronwald, Peter J OefnerAbstract:Amino Acids are important targets for metabolic profiling. For decades, Amino Acid Analysis has been accomplished by either cation-exchange or reversed-phase liquid chromatography coupled to UV absorbance or fluorescence detection of pre-column or post-column-derivatized Amino Acids. Recent years have seen great progress in the development of direct-infusion or hyphenated mass spectrometry in the Analysis of free Amino Acids in physiological fluids, because mass spectrometry not only matches optical detection in sensitivity, but also offers superior selectivity. The advent of cryo-probes has also brought NMR spectroscopy within the detection limits required for the Analysis of free Amino Acids. But there is still room for further improvement, including expansion of the analyte spectrum, reduction of sample preparation and Analysis time, automation, and synthesis of affordable isotope standards.
Marc R Wilkins - One of the best experts on this subject based on the ideXlab platform.
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large scale Amino Acid Analysis for proteome studies
Journal of Chromatography A, 1996Co-Authors: Marc R Wilkins, Keli Ou, Andrew A Gooley, Keith L Williams, Jeancharles Sanchez, Olivier Golaz, Christian Pasquali, Denis F HochstrasserAbstract:Amino-Acid Analysis is a relatively new method for identification of proteins separated by two-dimensional gel electrophoresis and blotted onto polyvinylidene difluoride (PVDF) membranes. This article describes modified Amino-Acid Analysis methods for this purpose. Streamlined sample handling is a key feature of the process. To minimise sample manipulation, a single vial is used for hydrolysis and the protein hydrolysate on PVDF membrane is extracted by a one-step procedure. The hydrolysate should not be stored for long periods before Analysis. Applications of the technique are presented to demonstrate the identification procedure. This approach is the most cost-effective and time-effective first step in mass protein screening for a large-scale proteome project.
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rapid protein identification using n terminal sequence tag and Amino Acid Analysis
Biochemical and Biophysical Research Communications, 1996Co-Authors: Marc R Wilkins, Keli Ou, Jeancharles Sanchez, Olivier Golaz, Denis F Hochstrasser, Ron D Appel, Vince Farnsworth, Paul K Cartier, Keith L WilliamsAbstract:Abstract Proteins can be identified by Amino Acid Analysis and database matching, but it is often desirable to increase the confidence in identity through the use of other techniques. Here we describe a rapid protein identification method that uses Edman degradation to create a 3 or 4 Amino Acid N-terminal “sequence tag,” following which proteins are subjected to Amino Acid Analysis protein identification procedures. Edman degradation methods have been modified to take only 23 min per cycle, and rapid Amino Acid Analysis techniques are used. The Edman degradation and Amino Acid Analysis is done on a single PVDF membrane-bound protein sample. A computer database matching program is also presented which uses both Amino Acid composition and “sequence tag” data for protein identification. This method represents the most inexpensive, accurate, and rapid means of protein identification, which is ideal for the screening of proteomes separated by 2-D gel electrophoresis. The creation of N-terminal Edman degradation “sequence tags” prior to peptide mass fingerprinting of samples should also be useful.
