Biomonitoring in workers exposed to pesticides: development and application of method detecting imidacloprid in urine

Abstract

Imidacloprid is a relatively new insecticide in neonicotinoids chemical class with neuroactivity in insects, being one of the most widely used insecticides in the world. For biomonitoring in workers exposed to pesticides, the authors designed a method detecting low levels of Imidacloprid in urine of operators, based on tandem liquid mass-spectrometry with ionization source - electrostatic dispersion (positive ionization) in multi-reaction monitoring regime with subsidiary ion (mass/charge) 209 for quantitative assessment and ion 175.1 for confirmation onion ratio. The study incorporated diurnal urine, about 100 ml of average sample was frozen and kept at temperature -20C for analysis. Before extraction, the sample was unfrozen, an aliquot of 5 ml was selected, diluted with 5 ml of 0.1% formic acid. The substance was concentrated out of the urine samples via solid-phase extraction with application of cartridges based on octadecylsilane, eluition - 1 ml of methanol. Lower limit of Imidacloprid detection in urine is 0.02 ng/ml, of the quantitative assessment - 0.1 ng/ ml, linear range of concentrations measured 0.1-10 ng/ml. The method was tested for monitoring in workers exposed to Imidacloprid preparations in natural conditions of pesticides application in agriculture, with various processing technologies. Imidacloprid was identified in urine of two professional operators after work in seed treatment and the subsequent seeding at lower limit of detection (0.02 ng/ml) and 0.34 ng/ml.