Simultaneous determination of phenol, cresol, xylenol isomers and naphthols in urine by capillary gas chromatography

An attempt was made to establish a method for the simultaneous determination of urinary concentrations of phenol, o-, p- and m-cresols, 1- and 2-naphthol and xylenol isomers by capillary gas chromatography. Urine samples were extracted after acid hydrolysis of glucuronides and sulfates by solid-phase extraction. The ten substances were separated gas chromatographically using a capillary column (Ultra 2) of cross-linked 5% phenylmethyl silicone. Calibration graphs were linear for 5-100 mu g/ml of all the phenols determined. The corresponding detection limits for phenolic compounds varied from 0.1 to 0.2 mu g/ml. The relative standard deviations for samples in urine were in the range 2.6-16.6% and the accuracy was in the range 1.4-25%. Recoveries were generally over 80%.