Development and validation of a method for the determination of 159 pesticide residues in tobacco by gas chromatography-tandem mass spectrometry.

A multiresidue gas chromatography-tandem mass spectrometry (GC-MS/MS) method was developed for the analysis of 159 multiclass pesticides in tobacco. A modified QuEChERS sample preparation technique, based on acetonitrile extraction and toluene dilution, followed by dispersive solid-phase extraction (d-SPE) cleanup using primary-secondary amine (PSA) and octadecyl (C18) sorbents, was used for sample treatment. Key performance parameters investigated were linearity, recovery, relative standard deviation (RSD), limit of detection, and limit of quantitation. With the exception of chinomethionate and folpet, recoveries for pesticides ranged from 69 to 141%, and the RSDs ranged from 2 to 27%. The validated method was applied to the analysis of 118 real samples, and positive results were obtained for 116 samples, with 25 different pesticides being detected.