miniaturization of the quechers method in the fast gas chromatography-tandem mass spectrometry analysis of pesticide residues in vegetables

Two reduced-scale quick, easy, cheap, effective, rugged, and safe (quechers) procedures, combined with fast gas chromatography-triple quadrupole mass spectrometry (gc-qqq ms), were developed and then validated for the determination of 35 pesticides in different vegetable products (tomatoes, zucchini, red peppers, and lettuce). the proposed reduced-scale methods, involving the use of only 3 g of sample, were compared with an official european union method, namely en15662:2008, based on the use of a 10-g sample. method validation was performed considering the following figures of merit: recovery, linearity, precision, matrix effects, and limits of detection and quantification. specifically, recovery was in the 67–126% range, regression coefficients were between 0.991 and 0.999, and coefficients of variation were between 1 and 13% (at the 50 μg kg−1 level), while limits of quantification were always below european legislation residue limits. additionally, the measurement of matrix effects confirmed the necessity of matrix-matched calibration. the developed quechers gc-qqq ms method is both simple and rapid (analysis of six samples in 2.5 h) and is sensitive enough for eu regulation purposes. to demonstrate the applicability of the proposed reduced-scale method, multi-residue analysis was performed on 20 samples.