%0 Journal Article
%A Thiele, B.
%A Füllner, K.
%A Stein, N.
%A Oldiges, M.
%A Kuhn, A. J.
%A Hofmann, D.
%T Analysis of amino acids without derivatization in barley extracts by LC-MS-MS
%J Analytical and bioanalytical chemistry
%V 391
%@ 1618-2642
%C Berlin
%I Springer
%M PreJuSER-62860
%P 2663 - 2672
%D 2008
%Z Record converted from VDB: 12.11.2012
%X A method has been developed for quantification of 20 amino acids as well as 13 (15)N-labeled amino acids in barley plants. The amino acids were extracted from plant tissues using aqueous HCl-ethanol and directly analyzed without further purification. Analysis of the underivatized amino acids was performed by liquid chromatography (LC)-electrospray ionization (ESI) tandem mass spectrometry (MS-MS) in the positive ESI mode. Separation was achieved on a strong cation exchange column (Luna 5micro SCX 100A) with 30 mM ammonium acetate in water (solvent A) and 5% acetic acid in water (solvent B). Quantification was accomplished using d (2)-Phe as an internal standard. Calibration curves were linear over the range 0.5-50 microM, and limits of detection were estimated to be 0.1-3.0 microM. The mass-spectrometric technique was employed to study the regulation of amino acid levels in barley plants grown at 15 degrees C uniform root temperature (RT) and 20-10 degrees C vertical RT gradient (RTG). The LC-MS-MS results demonstrated enhanced concentration of free amino acids in shoots at 20-10 degrees C RTG, while total free amino acid concentration in roots was similarly low for both RT treatments. (15)NO(3) (-) labeling experiments showed lower (15)N/(14)N ratios for Glu, Ser, Ala and Val in plants grown at 20-10 degrees C RTG compared with those grown at 15 degrees C RT.
%K Amino Acids: analysis
%K Calibration
%K Cations: chemistry
%K Chromatography, Ion Exchange: methods
%K Hordeum: chemistry
%K Hordeum: metabolism
%K Nitrogen Isotopes
%K Plant Extracts: analysis
%K Plant Leaves: chemistry
%K Plant Leaves: metabolism
%K Plant Roots: chemistry
%K Plant Roots: metabolism
%K Plant Shoots: chemistry
%K Plant Shoots: metabolism
%K Reproducibility of Results
%K Spectrometry, Mass, Electrospray Ionization: methods
%K Tandem Mass Spectrometry: methods
%K Amino Acids (NLM Chemicals)
%K Cations (NLM Chemicals)
%K Nitrogen Isotopes (NLM Chemicals)
%K Plant Extracts (NLM Chemicals)
%K J (WoSType)
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:18506428
%U <Go to ISI:>//WOS:000258083900030
%R 10.1007/s00216-008-2167-9
%U https://juser.fz-juelich.de/record/62860