Determination of neonicotinoid insecticides and their metabolites in honey bee and honey by liquid chromatography tandem mass spectrometry.

The original analytical method for the simultaneous determination and confirmation of neonicotinoids insecticides (imidacloprid, clothianidin, acetamiprid, thiametoxam, thiacloprid, nitenpyram, dinotefuran) and some of their metabolites (imidacloprid guanidine, imidacloprid olefin, imidacloprid urea, desnitro-imidacloprid hydrochloride, thiacloprid-amid and acetamiprid-N-desmethyl) in honey bee and honey was developed. Preparation of honey bee samples involves the extraction with mixture of acetonitrile and ethyl acetate followed by cleaned up using the Sep-Pak Alumina N Plus Long cartridges. Honey samples were dissolved in 1% mixture of acetonitrile and ethyl acetate with addition of TEA, then extracts were cleaned up with Strata X-CW cartridges. The identity of analytes was confirmed using liquid chromatography tandem mass spectrometry. All compounds were separated on a Luna C18 column with gradient elution. The whole procedure was validated according to the requirements of SANCO 12571/2013. The average recoveries of the analytes ranged from 85.3% to 112.0%, repeatabilities were in the range of 2.8-11.2%, within-laboratory reproducibility was in the range of 3.3-14.6%, the limits of quantitation were in the range of 0.1-0.5μgkg(-1), depending of analyte and matrices. The validated method was successfully applied for the determination of clothianidin, imidacloprid and imidacloprid urea in real incurred honey bee samples and clothianidin in honey.