Selected ion mass spectrometric identification of chlorophenol residues in human urine

A method is presented for the detection and confirmation of trace chlorophenol residues in environmental and biological samples by mass spectrometry with selected ion monitoring (SIM). Propionate and acetate ester derivatives of phenol, cresols, mono-, di-, tri-, and tetrachlorophenols, pentachlorophenol, as well as the internal standard 4,6-dibromo-o-cresol, were prepared directly in aqueous solution, using the appropriate anhydride reagent. The acetate or propionate esters were quantitatively extracted and then separated by gas-liquid chromatography using either an SP-1240DA or OV-101 packed column. Electron impact SIM was carried out by simultaneously monitoring up to 4 diagnostic fragment ions of each chlorinated phenol. The use of SIM eliminated background interference encountered using flame ionization or electron capture detectors, and allowed identification of chlorophenol residues in extracts of urine samples collected from individuals without known exposure to chlorophenols. Phenol concentrations as low as 1.0 pmol/mL urine gave peaks that were readily discernible by SIM.