Urinary phenylmercapturic acid as a marker of occupational exposure to benzene.
A hand-saving HPLC method to measure urinary phenylmercapturic acid (PMA) was developed which allows about 35 PMA determinations per day. The method involves conversion of pre-PMA to PMA by the addition of sulfuric acid to a urine sample, extraction into an ether-methanol mixture followed by condensation under a nitrogen stream. The condensate was introduced to a ODS-3 column in a HPLC system, and PMA in the column was eluted into a mobile phase of acetonitrile: methanol: perchloric acid: water. The elution of PMA was monitored at 205 nm. One determination will be completed in 40 min. The method was applied to analysis of end-of-shift urine samples from 152 workers exposed up to 210 ppm benzene, 66 workers exposed to a mixture of benzene (up to 116 ppm) and toluene + xylenes (up to 118 ppm), and 131 non-exposed controls of both sexes. A linear regression was established between time-weighted average intensity of exposure to benzene and urinary PMA. From the regression, it was calculated that urinary PMA level will be about 6.4 mg/l after 8-hour exposure to benzene at 100 ppm, and that PMA in urine accounted for about 0.1% of benzene absorbed. No effects of sex, age, and smoking habit of individuals were detected, and the effect of co-exposure to toluene + xylenes at the levels comparable to that of benzene was essentially nil, which indicates an advantage of PMA as a benzene exposure marker over monoto tri-phenolic metabolites or t,t-muconic acid.
Inoue
O
O
Tohoku Rosai Hospital, Sendai, Japan.
Kanno
E
E
Kakizaki
M
M
Watanabe
T
T
Higashikawa
K
K
Ikeda
M
M
D000111:Acetylcysteine / Q000031:analogs & derivatives* / Q000652:urine; D000328:Adult; D000367:Age Factors; D001554:Benzene / Q000009:adverse effects* / Q000032:analysis; D015415:Biomarkers / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D016273:Occupational Exposure / Q000032:analysis*; D012044:Regression Analysis; D012737:Sex Factors; D012907:Smoking
D015415:Biomarkers; C053003:S-phenyl-N-acetylcysteine; D001554:Benzene; D000111:Acetylcysteine