Determination of dichloroanilines in human urine by GC-MS, GC-MS-MS, and GC-ECD as markers of low-level pesticide exposure

Methods for the determination of 3,4-dichloroaniline (3,4-DCA) and 3,5-dich loroaniline (3,5-DCA) as common markers of eight non-persistent pesticides in human urine are presented. 3,5-DCA is a marker for the exposure to the f ungicides vinclozolin, procymidone, iprodione, and chlozolinate. Furthermor e the herbicides diuron, linuron, neburon, and propanil are covered using t heir common marker 3,4-DCA. The urine samples were treated by basic hydroly sis to degrade all pesticides, metabolites, and their conjugates containing the intact moieties completely to the corresponding dichloroanilines. Afte r addition of the internal standard 4-chloro-2-methylaniline, simultaneous steam distillation extraction (SDE) followed by liquid-liquid extraction (L LE) was carried out to produce, concentrate and purify the dichloroaniline moieties. Gas chromatography (GC) with mass spectrometric (MS) and tandem m ass spectrometric (MS-MS) detection and also detection with an electron-cap ture detector (ECD) after derivatisation with heptafluorobutyric anhydride (HFBA) were employed for separation, detection, and identification. Limit o f detection of the GC-MS-MS and the GC-ECD methods was 0.03 and 0.05 mug/l, respectively. Absolute recoveries obtained from a urine sample spiked with the internal standard, 3,5-, and 3,4-DCA, ranged from 93 to 103% with 9-18 % coefficient of variation. The three detection techniques were compared co ncerning their performance, expenditure and suitability for their applicati on in human biomonitoring studies. The described procedure has been success fully applied for the determination of 3,4- and 3,5-DCA in the urine of non -occupationally exposed volunteers. The 3,4-DCA levels in these urine sampl es ranged between 0.13 and 0.34 mug/g creatinine or 0.11 and 0.56 mug/l, wh ile those for 3,5-DCA were between 0.39 and 3.33 mug/g creatinine or 0.17 a nd 1.17 mug/l. (C) 2001 Elsevier Science B.V. All rights reserved.