SENSITIVE GAS-CHROMATOGRAPHIC METHOD FOR DETERMINATION OF MERCAPTURICACIDS IN HUMAN URINE

A method was developed for sensitive determination of the specific ben zene metabolite S-phenylmercapturic acid and the corresponding toluene metabolite S-benzylmercapturic acid in human urine for non-occupation al and occupational exposure. The sample preparation procedure consist s of liquid extraction of urine samples followed by precolumn derivati zation and a clean-up by normal-phase HPLC. Determination of analytes occurs by gas chromatography with electron-capture detection. With thi s highly sensitive method (detection limits 60 and 65 ng/l, respective ly) urinary S-phenylmercapturic and S-benzylmercapturic acid concentra tions for non-occupationally exposed persons (e.g. non-smokers) can be measured precisely in one chromatographic run. Validation of the meth od occurred by comparison with a HPLC method we have published recentl y.