Styrene metabolism in man: gas chromatographic separation of mandelic acid enantiomers in the urine of exposed persons.

D- and L-mandelic acid are separated by gas chromatography as isopropyl ester or isopropyl ester-isopropyl urethane on capillary columns, coated with Chirasil -Val. For its determination in urine the isopropyl ester procedure gives better results because other components of the urine do not cause interference. Thus D- and L-mandelic acid in the urine of exposed workers could be detected and verified by means of GC/MS. Occupational styrene exposure near the MAK-value (100 ppm) results in a L/D-enantiomer-ratio in urine of nearly 1.5.