Insecticides of neonicotinoides class: determining exposure via workers' urine

For biomonitoring of exposure in workers with insectocaricides, the authors created a method of multi-component assessment oflowlevels of neonicotinomides in workers' urine, based on last generation tandem liquid mass-spectrometry (triple quadrupole) with ionization source - electrostatic dispersion (positive ionization) in dynamic multi-reaction monitoring with two transitions of parent ions (for quantitative assessment and ionic ratio confirmation). After the work, the operators gave urine samples (about 100 ml in average) that were frozen and kept under -20⁰C before analysis. Samples were defrozen before analysis, and each urine portion of 5 ml was diluted by equal volume of 0,1% formic acid. To extract substances out of the samples, solid-phase extraction (cartridges based on octadecylsilane) was applied, elution was performed with 1 ml of methanol. Lower limit of the substances detection in urine - 0,02-0,05 ng/ml, lower limit of the quantitative assessment - 0,1-0,2 ng/ml. The method was tested on monitoring of the workers' exposure to preparations based on imidaclopride and clotianidine in natural conditions of pesticides use in agriculture with various processing technologies. midacloprid was identified in urine of 3 professional operators after wheat and oat seeds treatment and after subsequent seeding at lower limit of detection (0,02 ng/ml), lower limit of quantitative assessment (0,1 ng/ ml) and 0,34 ng/ml.