TY  - JOUR
AU  - Thiele, B.
AU  - Füllner, K.
AU  - Stein, N.
AU  - Oldiges, M.
AU  - Kuhn, A. J.
AU  - Hofmann, D.
TI  - Analysis of amino acids without derivatization in barley extracts by LC-MS-MS
JO  - Analytical and bioanalytical chemistry
VL  - 391
SN  - 1618-2642
CY  - Berlin
PB  - Springer
M1  - PreJuSER-62860
SP  - 2663 - 2672
PY  - 2008
N1  - Record converted from VDB: 12.11.2012
AB  - 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.
KW  - Amino Acids: analysis
KW  - Calibration
KW  - Cations: chemistry
KW  - Chromatography, Ion Exchange: methods
KW  - Hordeum: chemistry
KW  - Hordeum: metabolism
KW  - Nitrogen Isotopes
KW  - Plant Extracts: analysis
KW  - Plant Leaves: chemistry
KW  - Plant Leaves: metabolism
KW  - Plant Roots: chemistry
KW  - Plant Roots: metabolism
KW  - Plant Shoots: chemistry
KW  - Plant Shoots: metabolism
KW  - Reproducibility of Results
KW  - Spectrometry, Mass, Electrospray Ionization: methods
KW  - Tandem Mass Spectrometry: methods
KW  - Amino Acids (NLM Chemicals)
KW  - Cations (NLM Chemicals)
KW  - Nitrogen Isotopes (NLM Chemicals)
KW  - Plant Extracts (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:18506428
UR  - <Go to ISI:>//WOS:000258083900030
DO  - DOI:10.1007/s00216-008-2167-9
UR  - https://juser.fz-juelich.de/record/62860
ER  -