Method Development for Pesticide Residue Analysis in Cereal Grains and Pulses using GC-MS/MS

Abstract

         Cereal grains and pules are the most common consumed foods worldwide and the use of pesticides in agricultural production for plant protection has been the cause for increasing concern. The safety of these products must be checked for toxic pesticide residue contamination by reliable and trustable analytical method. The efficiency of QuEChERS and FaPEx^® method for sample preparation procedure was compared. A modified QuEChERS method was selected and was improved for simultaneous determination of 122 pesticide residues in rice and dried soybeans and the method was established and validated. The samples were initially extracted with acetonitrile (MeCN) and combined with salting out step by the mixture of MgSO₄ and CH₃COONa. The final extract was concentrated and reconstituted with appropriate solvent. The target pesticides were detected by gas chromatography-tandem mass spectrometry (GC-MS/MS) with MRM  echnique to minimized interference. The limit of detection and the limit of quantification of the validated method were 0.02 and 0.05 mg/kg for the pesticides respectively. Analysis of fortified rice and dried soybean samples were performed at three different levels (0.05, 0.2 and 1.25 mg/kg). Mean recoveries from eight  eplicates ranged from 74.3-119.8%, with relative standard deviation, RSD lower than 20. The evaluation  howed that the QuEChERS method held excellent linearity at 0.05-2.5 mg/kg (r > 0.995). The participation in PT scheme for external quality control showed the satisfactory results and internal quality control was applied for routine analysis. Based on our results, the developed method was successfully applied for the detection and quantification of pesticide residues in rice and cereal grains for health concern and regulatory propose.