ENANTIOSELECTIVE MULTIDIMENSIONAL GAS-CHROMATOGRAPHY MASS-SPECTROMETRY IN THE ANALYSIS OF URINARY ORGANIC-ACIDS

Enantioselective multidimensional gas chromatography-mass spectrometry is a valuable tool for the enantioselective analysis of compounds fro m complex matrices. Samples are separated initially on a precolumn and selected substances then transferred on-line to a main-column coated with suitable chiral stationary phase for enantioselective analysis wi th subsequent mass selective detection. In this paper the method is us ed as an adjunct to urinary organic acid analysis to provide informati on in patients with suspected inborn errors of metabolism. Lactic acid , alpha-hydroxyisocaproic acid, 3-phenyllactic acid and 3-(4-hydroxyph enyl)-lactic acid are separated in a single run. In addition, the enan tioselective analysis of pyroglutamic acid is presented. D-Enantiomers of amino acids and alpha-hydroxycarboxylic acids derived from amino a cids, point to a bacterial origin whereas the L-enantiomer is predomin antly of endogenous origin. Therefore the enantiomeric ratio of chiral metabolites is an important parameter for the understanding of metabo lic processes. (C) 1998 Elsevier Science B.V. All rights reserved.