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Amino Acid Analysis

The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform

Peter J Oefner – 1st expert on this subject based on the ideXlab platform

  • urinary Amino Acid Analysis a comparison of itraq lc ms ms gc ms and Amino Acid analyzer
    Journal of Chromatography B, 2009
    Co-Authors: Hannelore Kaspar, Katja Dettmer, Queenie Chan, Scott Daniels, Subodh B Nimkar, Martha L Daviglus, Jeremiah Stamler, Paul Elliott, Peter J Oefner

    Abstract:

    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.

  • advances in Amino Acid Analysis
    Analytical and Bioanalytical Chemistry, 2009
    Co-Authors: Hannelore Kaspar, Katja Dettmer, Wolfram Gronwald, Peter J Oefner

    Abstract:

    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 – 2nd expert on this subject based on the ideXlab platform

  • Recent advances in Amino Acid Analysis by capillary electromigration methods: June 2015-May 2017
    Electrophoresis, 2017
    Co-Authors: Véréna Poinsot, Pierre Gavard, Varravaddheay Ong-meang, Lucie Perquis, François Couderc

    Abstract:

    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.

  • Recent advances in Amino Acid Analysis by capillary electrophoresis
    Electrophoresis, 2012
    Co-Authors: Véréna Poinsot, Marie Anne Carpéné, Jalloul Bouajila, Pierre Gavard, Bernard Feurer, François Couderc

    Abstract:

    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.

  • Recent advances in Amino Acid Analysis by capillary electrophoresis.
    Electrophoresis, 2011
    Co-Authors: Véréna Poinsot, Marie Anne Carpéné, Jalloul Bouajila, Pierre Gavard, Bernard Feurer, François Couderc

    Abstract:

    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.

Wei Du – 3rd expert on this subject based on the ideXlab platform

  • recent advances in microchip electrophoresis for Amino Acid Analysis
    Analytical Abstracts, 2013
    Co-Authors: Gaozhi Ou, Xiaojun Feng, Wei Du

    Abstract:

    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).

  • recent advances in microchip electrophoresis for Amino Acid Analysis
    Analytical and Bioanalytical Chemistry, 2013
    Co-Authors: Gaozhi Ou, Xiaojun Feng, Wei Du

    Abstract:

    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.