QuEChERS METHOD FOR DETERMINATION OF PESTICIDE RESIDUES IN CHERRIES

simple multiresidue method was evaluated for the determination of pesticide residues in cherries using GC-MS/MS for the analysis. A modified QuEChERS method was evaluated in the coloured matrix, such as cherries. This extraction method involves sample extraction with acetonitrile for 3 min on vortex mixer and permits the salt-out liquid−liquid partitioning step using magnesium sulfate anhydrous, sodium chloride, trisodium citrate dihydrate and sodium citrate dibasic sesquihydrate. After shaking and centrifugation, the cleanup was done by adding 5 ml of extract to anhydrous MgSO4, PSA, and carbo activatus. After a repeated centrifugation the 2 ml of extract was evaporated to dryness, and reconstituted in 2 ml of acetone. The optimized analytical conditions were evaluated in terms of recoveries, reproducibility, limits of detection, and matrix effects for 17 pesticides. Some significant matrix effects observed for most of the tested pesticides were eliminated using matrix-matched calibration. The linearity was studied in the range of 0.05–1.0 μg/ml with the R2 higher than 0.99. The recovery data were obtained by spiking blank samples at three concentration levels (0.05, 0.1 and 0.5 mg/kg) yealding recoveries in the range of 77.5–102.4%. The precision values were lower than 11.14% for the intraday precision. The LOQs were established as 10 μg/kg.