ENDOGENOUS ALKALOIDS IN MAN .21. ANALYSIS OF GLYOXYLATE-DERIVED 1,3-THIAZOLIDINES AND THEIR PRECURSORS AFTER TRIMETHYLSILYLATION BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY

摘要

A gas chromatographic procedure was developed for the simultaneous analysis of glyoxylate-derived 1,3-thiazolidines and their precursors, such as L-cysteine, cysteamine, and D-(-)-penicillamine as well as the toxic glyoxylic acid. The assay involves conversion of these highly polar compounds to volatile trimethylsilyl (TMS) derivatives, chromatography on a polar fused-silica capillary column, and determination using flame-ionization detection or electron-impact ionization mass spectrometry. On the base of this analytical device, the resolution of the diastereomeric pairs of 1,3-thiazolidine-2,4-dicarboxylic acids was achieved. Based upon the observation that no epimerization occurs during the silylation procedure, for the first time a reliable method was established for the determination of the diastereomeric ratio of such alkaloid-type heterocycles on a trace scale. Furthermore, studies concerning thiazolidine formation under derivatization conditions in the presence of the precursors glyoxylic acid and D-(-)-penicillamine are described. [References: 44]