Multiresidue Method for the Determination of Pesticides in Fruits and Vegetables Using Gas Chromatography-Negative Chemical Ionization-Triple Quadrupole Tandem Mass Spectrometry

The feasibility of gas chromatography-negative chemical ionization-triple quadrupole tandem mass spectrometry (GC-NCI-MS-MS), as a routine multiresidue method for simultaneous analysis of 82 pesticides in fruits and vegetables, was investigated. The precursor ions, product ions and collision energy were selected using experiments, and 164 different multiple reaction monitoring (MRM) transitions were monitored simultaneously in one run. Prior to GC-NCI-MS-MS analysis, co-extractives were removed from the concentrated acetonitrile extracts by using dispersive solid phase extraction with octadecyl (350 mg) and primary secondary amine (100 mg) sorbents. Large volume injection (10 A mu L) combined with a temperature-programmed vaporizer (PTV) system of gas chromatography was used to improve the sensitivity of analytes. To evaluate performance of this method, validation experiments were carried out on cabbage and apples at two spiking levels (10 and 20 mu g kg(-1)). The average recoveries ranged between 58.7 and 124.4% with intra-day relative standard deviations (RSD) between 3.9 and 15.9%. The limits of detection (LOD), limits of confirmation (LOC) and limits of quantification (LOQ) of all pesticides were below its maximum residue levels (MRLs). The proposed method was successfully applied in the analysis of fruits and vegetables.