Determination of chlorpyrifos-methyl, lambda-cyhalothrin and tebuconazole residues in Sultana seedless grapes sprayed with pesticides under farmer’s conditions

The aim of this study was to investigate pesticide residues on Sultana Seedless Grapes harvested at different times and consequently evaluate the risk. Analyses were performed with the Quick-Easy-Cheap-Efficient-Rugged-Safe (QuEChERS)-liquid chromatography/tandem mass spectrometry (LC-MS/MS) procedure. Pesticide-free grapes were spiked at 3 levels. Chlorpyrifos-methyl, lambda-cyhalothrin and tebuconazole detection limits were 20, 10 and 1 µg kg-1, respectively. These values were below maximum residue levels (MRL) of 1000, 80 and 500 µg kg-1, respectively. The overall recovery of the method was 108.60%. Present values were within acceptable recovery (60-140%) and repeatability (≤20%) ranges set by the Directorate-General for Health and Food Safety (SANTE). The vineyards were sprayed 4 times. Grapes were harvested in the 1st, 3rd, 5th, 7th and 14th days from the last spray. The residues in the samples taken from 5 vine stock groups were determined. MRL-exceeding chlorpyrifos-methyl residue of 1140.09 µg kg-1 was detected in the 1st day. The MRL-exceeding lambda-cyhalothrin (381.15 and 307.39 µg kg-1) and tebuconazole residues (650.58 and 570.85 µg kg-1) were detected in the 1st and 3rd days, respectively. The residues of 7th and 14th day samples were significantly different from the others. Excessive pesticide concentrations did not pose any health risks on consumers.