Gas chromatographic method with mass-selective detection for the determination of 2-isopropoxyphenol in human urine

Human metabolism of the insecticide propoxur yields 2-isopropoxyphenol (IPP) which is excreted conjugated in urine. In this publication a sensitive and selective analytical method is described which permits the determination of IPP as a suitable parameter for biomonitoring. The clean-up of the hydrolysed urine samples consisted of steam distillation and solid-phase extraction using a reversed-phase column. IPP and the internal standard 2-ethoxyphenol were converted to their pentafluorobenzyl ethers. Excess of the derivatisation reagent was removed using deactivated silica gel. Separation and quantitative analysis was carried out by capillary gas chromatography and mass selective detection. Coefficients of variation were below 5% for concentrations from 6 to 300 microg/l. The detection limit was 0.5 microg/l. The method was checked by analysing six urine samples from pest controllers after indoor application of propoxur. The IPP concentrations ranged from 45 to 306 microg/g creatinine. IPP was not detected in urine specimens from 10 non-exposed persons. The sensitivity of the developed method permits the detection of latent exposure to propoxur.