Multi-class pesticide analysis in human hair by gas chromatography tandem (triple quadrupole) mass spectrometry with solid phase microextraction and liquid injection

A method for the simultaneous detection and quantification of 22 pesticides from different chemical classes was developed using solid-phase microextraction (SPME) and gas chromatography tandem (triple quadrupole) mass spectrometry. Pesticides were extracted from 50 mg of pulverized hair with acetonitrile. The extract was submitted to two successive steps of direct immersion-SPME at 30 °C and 90 °C or to a liquid injection without SPME in order to obtain optimized conditions for each of the 22 analytes investigated. Validation parameters were significantly influenced by both the injection mode (SPME vs liquid injection) and the temperature of SPME. Limits of quantification ranged from 0.05 pg mg⁻¹ for trifluralin to 10 pg mg⁻¹ for pentachlorophenol. The application of the validated method to the analysis of samples collected from non-occupationally exposed volunteers demonstrated the presence of pesticides in all the samples tested. Altogether, 13 different analytes were detected at concentration above the limit of quantification.