Determination of chlorfenapyr in leek grown under greenhouse conditions with GC-μECD and confirmation by mass spectrometry

A simple analytical method was developed for the determination of chlorfenapyr residues in leeks grown under greenhouse conditions. Residues were extracted by salting out, analyzed by gas chromatography with microelectron-capture detection, and confirmed via gas chromatographymass spectrometry. The calibration curves were found to be linear with correlation coefficients (r2) in excess of 0.998. The limits of detection and quantification were 0.0015 and 0.005 mg kg-1, respectively. For validation purposes, recovery studies were carried out at low and high levels. Yield recovery rates were 87.2789.64% with a relative standard deviation <6%. A maximum of 0.32 mg kg-1 of chlorfenapyr residue was detected in leek sample sprayed three times at 7 day intervals until 7 days prior to harvest. The results of this study suggest that chlorfenapyr is acceptable for application in/on leeks under the recommended dosage regimen. Copyright (C) 2011 John Wiley & Sons, Ltd.