Determination of imidacloprid and indoxacarb residues in apple and it’s processed products

Pesticide residues are important in raw agricultural products and their processed products. In this study, imidacloprid and indoxacarb pesticides were applied to "Golden Delicious" apples. Residue analyses were performed by using QuEChERS method and LC-MS/MS. In apples, imidacloprid and indoxacarb residues (mean of sampled 3 days after the application and 14 days after the application), were 170.60 and 490.77 μg/kg, respectively. Imidacloprid residues in the peel, pulp, pre-juicing, full processed-juice and bagasse were 791.14, 104.17, 44.60, 47.41 and 262.57 μg/kg, respectively, as the mean of both harvest periods. For indoxacarb, residues were 2195.07 μg/kg in the peel, 197.84 μg/kg in the pulp, 82.26 μg/kg in the pre-juicing and 597.17 μg/kg in the bagasse. The processing factors (Pf) of each process were calculated as a reduction or concentration factor. Imidacloprid residues in the peel and baggase were 4.67 and 1.55 times (mean of two harvesting time) higher than apple, respectively.The residues of pulp, pre-juicing, full processed-juice reduced by 39.75%, 73.54% and 70.62%, respectively. Indoxacarb residues in the peel and baggase were increased 4.46 and 1.21 times, respectively. The mean reduction rates were 59.84% in pulp and 83.35% in pre-juicing. The difference between the decrease in residual reduction rates and the rate of residual degradation between the harvest process in the full process fruit juice was significant at 1% level. The residues of processes, calculated based on Pf, were below MRL (500 μg/kg) for both insecticides. Residues in peel and baggase were increased regardless of harvest period and pesticide