CONICET | Buscador de Institutos y Recursos Humanos

Chlorpyrifos (CPF) is an organophosphorus insecticide widely used to control insect pests in crops and foods. Currently dietary intake is the main source of exposure to CPF for the general population, since the ANMAT (National Administration of Drugs, Foods and Medical Devices of Argentina) has banned the use of CPF in formulations of household sanitary products since 2008. Some studies correlate the presence of CPF in umbilical cord blood (UCB) with adverse effects in birth and long-term neurodevelopment, at exposure levels that do not cause maternal toxicity.1 As part of a study to correlate food habits in pregnant women with harmful effects in newborns and babies during the first year of their life, a rapid, selective and sensitive UPLC-MSMS method was developed for detection and quantification of CPF in UCB.A Waters Xevo TQ-S mass spectrometer coupled to an Acquity UPLC H-Class was used with an Acquity UPLC BEH C8 column (1.7 microns, 2.1 x 50 mm).After UCB sample centrifugation, plasma proteins were precipitated with acetonitrile containing 2-phenoxybenzoic acid as internal standard (ISTD). After mixing and centrifugation, the supernatant was transferred into a sample vial, diluted with an equal volume of 0.005% aqueous formic acid (FM A), and injected into the UPLC.The chromatographic gradient started at 50% of FM A and 50% of FM B (0.005% formic acid in acetonitrile) at a flow rate of 0.35 ml/min, followed by a linear increase to 90% of FM B at 2 minutes, and then back to the initial condition from 3.1 to 5 minutes. The total run time was 5 min. Calibration range: 0.5 to 100 ng/ml. Limit of detection (LOD): 0.3 ng/ml.CPF and ISTD were detected in ESI positive ionization mode. Samples were acquired in multiple reaction monitoring (MRM) mode and were processed using MassLynx 4.1 software. The MRM transitions monitored were: m/z 350>198 for CPF and m/z 215>115 for ISTD.392 umbilical cord blood samples from infants born at the Hospital Italiano de Buenos Aires between 2013 and 2014 were analyzed. CPF concentrations above the LOD were obtained in 13% of the total samples. 7.4% of the total were quantitated, the mean concentration of CPF in cord blood was 0.8 ng/ml (SD: 0.5, range: 0.5 ? 2.8 ng/ml).For assessing the impact of exposure to CPF on the fetus, the concentration of CPF in maternal or cord blood is a better indicator compared to the urinary concentration of its major metabolite 3,5,6-trichloro-2-pyridinol (TCPy), since the latter compound is a product of both metabolism and environmental degradation of CPF. Therefore, measurement of urinary TCPy cannot distinguish between direct exposure to CPF and exposure to the degradation products of CPF in the environment.2