Multiresidue analysis of over 200 pesticides in cereals using a QuEChERS and gas chromatography-tandem mass spectrometry-based method.

A simple and high-throughput multiresidue pesticide analysis method was developed and validated for 219 pesticides in cereals (corn, wheat flour and rice) based on QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure combined with gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS). Different buffer system (acetate- and citrate-buffered) and sample to solvent ratios (sample amount) were compared in the modified QuEChERS procedure to get better recovery and clean-up results. The limits of quantification (LOQ) ranged between 5 and 50μgkg(-)(1), and for the majority of the pesticides the LOQ were 5μgkg(-)(1), which were below the regulatory maximum residue limits. The coefficient of determination (r(2)) was >0.99 within the calibration linearity range of 2-200μgkg(-)(1) for the majority of the pesticides. Most recoveries at 5, 10, 20, 50, 100 and 200μgkg(-)(1) were in the range 70-120% (n=6) with associated RSDs<20% indicating satisfactory accuracy.