Isotope dilution high-performance liquid chromatography-tandem mass spectrometry method for quantifying urinary...

This paper describes a method for measuring cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acids (cis-DCCA and trans-DCCA), cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (DBCA), 3-phenoxybenzoic acid (3PBA), and 4-fluoro-3-phenoxybenzoic acid (4F3PBA) in human urine. These compounds are considered to be reliable biomarkers of exposure for many pyrethroid insecticides used in the United States. In this method, stable isotopically labeled analogues of trans-DCCA and 3PBA were spiked into urine as internal standards. After solid-phase extraction, the extracts were analyzed by high-performance liquid chromatography coupled with tandem mass spectrometry using turbo ion-spray atmospheric pressure ionization. The limits of detection (LODs) ranged from 0.1 to 0.5 microg/L. Within-day relative standard deviations ranged from 1.8 to 13% and between-day relative standard deviations ranged from 0.5 to 18%. Absolute analyte recoveries ranged from 72 to 93%. Chromatographic retention times were less than 8 min. This method was used to measure urinary concentrations of these metabolites in persons with no known exposure to pyrethroids and some with suspected residential exposure. Metabolites of synthetic pyrethroids were detected in 74% of the samples analyzed. cis-DCCA, trans-DCCA, DBCA, 4F3PBA, and 3PBA were detected in 36, 50, 3, 9, and 64% of the samples analyzed, respectively.