The aim of this study was to develop a sample-preparation method involving water-based extraction and versatile SPE clean-up for simultaneous determination of seven hydrophilic neonicotinoid insecticides as well as some of the major metabolites in agricultural samples by means of LC-MS/MS. The effects of sample matrix on detection of the target compounds were negligibly small. Mean recoveries obtained at spiked concentrations between 0.01 and 1.00 mg/kg were 71.2-122.3% with relative standard deviations of =7.5%. To verify the applicability of the proposed sample-preparation method, we compared analytical results obtained using the proposed method for samples prepared by spraying crops with several commercial neonicotinoid insecticide formulations with results obtained by means of a reference method (the official Japanese multiresidue method). The residual concentrations of the compounds determined by the proposed method (0.015�0.27 mg/kg in green peppers and 0.017�0.31 mg/kg in tomatoes) were equivalent to those determined by the official Japanese method (0.017�0.26 mg/kg in green peppers and 0.013�0.30 mg/kg in tomatoes). The proposed method for agricultural samples here demonstrates that (1) the consumed volume of organic solvent (25 mL per sample) is much less than the volume consumed by the official Japanese multiresidue method (150 mL per sample) and (2) that it has simple procedures without liquid-liquid partitioning and can simultaneously and suitably recover hydrophilic pesticides as well as polar metabolites such as CPMA and CPMF that cannot be simultaneously recovered by the official Japanese multiresidue method.

Water-based extraction and liquid chromatography�tandem mass spectrometry analysis of neonicotinoid insecticides and their metabolites in green pepper/tomato samples

248th National Meeting (2014)

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