Suspect screening and targeted analyses: Two complementary approaches to characterize human exposure to pesticides

Highlights: • Suspect screening and target analyses were combined for mixture identification. • Both approaches were used on the same urine samples from pregnant women. • Exposure to various pesticide families occurred both in rural and urban areas. • Suspect screening identified highly detected metabolites that are rarely studied. • Target analysis is a complementary approach for the quantification of specific compounds. Characterizing human exposure to pesticides is challenging because their metabolites have a broad diversity of chemical structures. We aimed to study the interest of associating suspect screening and targeted analysis to identify multiple pesticide exposure of pregnant women. Approximately 300 urinary samples collected during early pregnancy (France) were analyzed by UHPLC/HRMS using both a suspect screening approach and targeted multiresidue analysis. Sixty-eight pesticides were selected according to available data on agricultural practices and analytical feasibility and 435 known or putative metabolites were added based on the literature. Compounds detected using the two approaches were compared and the place of residence was studied as a determinant of exposure for illustrative purposes. Suspect screening resulted in the characterization of 28 pesticide metabolites, corresponding to three fungicides (azoxystrobin, fenpropimorph, and procymidone), three herbicides (an arylphenoxypropionic acid derivative, chlorpropham, and phenmedipham), and one insecticide (carbofuran). The targeted approach led to the identification of pyrethroids, organophosphorus, fluazifop-P-butyl, and chlorpyrifos in >60% of samples and prochloraz, bromoxynil, diazinon, and procymidone in 10 to 50%. Both urban and rural areas were identified as being determinants of exposure, depending on the active substance. This combined strategy better characterizes pesticide mixtures. Suspect screening allows the detection of metabolites of pesticides that are rarely studied and not measured in biomonitoring studies, mainly because it allows the detection of conjugated phase II metabolites (azoxystrobin and fenpropimorph). The targeted approach complements it with the detection of highly polar and low molecular-weight metabolites, the confirmation of the parent compound, and the quantification of compounds for which analytical standards are commercially available or may be synthesized (organophosphorous, pyrethroids, and fluazifop-P-butyl). In addition, we detected several metabolites that have never been described in humans (fenpropimorph and azoxystrobin), which deserve to be candidates in the selection of markers of exposure.