HPLC-MS Determination of Amino Acids in Plants and Soil of Qing-Zang Plateau

HPLC-MS was applied to the determination of amino acids in plants and soil of Qing-Zang plateau. The amino acids were extracted from the sample with 6 mol·L-1 HCl solution and derivatized with 1,2-benzo-3,4-dihydrocarbazole-9-ethyl chloroformate (BCEOC). The derivatized products were separated by gradient elution with mixed solution of acetonitrile and water of different ratios on Hypersil BDS C18 column (4.6 mm×200 mm, 5 μm). The amino acids were determined by fluorescence detector at the wavelength of 333 nm (λex) and 390 (λem) and identified by MS with ESI+. Detection limits (3S/N) found were in the range of 6.3×10-15-1.8×10-13mol. Standards of 20 amino acids were added to extracts of soil sample and tested for the recovery; values of recovery obtained were in the range from 89.0% to 107.0%.