Analysis of ortho-cresol in urine by solid phase microextraction-capillary gas chromatography

Abstract

The object of the present study was the development of method for the determination of urinary ortho-cresol using solid-phase microextraction (SPME), followed by capillary gas chromatography-flame ionization detection (GC/FID). After optimization of the SPME variables and validation of the method, it was applied to analysis of o-cresol in urine collected from 27 workers exposed to solvents in automotive repair shops. The maximum extraction efficiency was obtained using fiber of carbowax-divinylbenzene (CW/DVB), 70 μm, immerged 20 min in acid hydrolysed urine added with 3 g Na2SO4 at pH 7.0 and under magnetic stirring. The method showed linearity between 0.1 to 1.5 mg L-1, LOQ of 0.1 mg L-1, precision between 6.8 to 7.8% CV. Mean o-cresol in urine from exposed workers was 0.35 ± 0.23 mg L -1. The SPME-GC/FID method is fast, simple and can be applied to the occupational toluene biomonitoring. ©2007 Sociedade Brasileira de Química.