Simultaneous determination of fatty, dicarboxylic and amino acids based on derivatization with isobutyl chloroformate followed by gas chromatography - Positive ion chemical ionization mass spectrometry

Abstract

Gas chromatography-mass spectrometry (GC-MS) with positive ion chemical ionization (PICI) using isobutane as reagent gas was applied for analysis of isobutoxycarbonyl/isobutyl derivatives of 13 fatty, 6 dicarboxylic and 13 amino acids in a single run. For all investigated compounds (except several amino acids) the quasimolecular ions [MH]+ were registered. Asparagine underwent fragmentation via decarboxylation followed by elimination of OC 4H9 ([M-117]+), whereas serine and tyrosine produced the cluster ions [M+C4H9OCO]+. Estimated detection limits were 6-250pg in the total ion current (TIC) mode and 3-10 times lower using the selected-ion monitoring (SIM) mode. © 2003 Elsevier B.V. All rights reserved.