[Level of urinary phenol and hippuric acid in control subjects and subjects exposed to benzene and toluene].

Two high-performance liquid chromatographic methods are described, one for assay of phenol in urine, the other for assay of hippuric acid. Steam distillation was used to hydrolyse the sample and separate the phenol from the matrix. A dilution was the only pretreatment of urine for assay of hippuric acid. The upper reference limits obtained from 42 non-exposed subjects were 7.09 mmol/mol creatinine for urinary phenol and 1,174 mmol/mol creatinine for hippuric acid. The mean concentration of urinary phenol was higher in 190 exposed workers (7.21 +/- 5.05 mmol/mol creatinine; mean +/- SD) than in control subjects (3.97 +/- 1.56 mmol/mol creatinine).