Residual determination of clothianidin and its metabolites in three minor crops via tandem mass spectrometry

A determination method for clothianidin and its metabolites (MNG, TMG, TZMU, and TZNG) in crown daisy, sedum, and amaranth grown under greenhouse conditions has been developed. The target compounds were identified and quantitatively determined using liquid chromatography coupled to tandem mass spectrometry. The matrix-matched calibration curves, used for quantification of the field-incurred analyte residues, were linear with coefficients of determination (r(2)) exceeding 0.99. The matrix effects ranged from -61.4 +/- 3.6 to 328.3 +/- 26.9 in three different crops. The limits of detection and quantitation were in the ranges of 0.01-0.04 and 0.04-0.16 mg/kg, respectively. The mean recoveries of the analytes ranged between 71.7% and 120.3%. The validated method developed herein was successively applied for the determination of clothianidin and its four metabolites in field-incurred samples. The parent compound, clothianidin, was identified as the main residue and the metabolite residues were variable in the treated crown daisy, sedum, and amaranth samples. (C) 2011 Elsevier Ltd. All rights reserved.