VALIDATION STUDY OF QUECHERS METHOD FOR DETERMINATION OF DIAZINON RESIDUES IN APPLE FRUITS.

The present study aimed to throw light on the dissipation and residual levels of diazinon in apple fruits under open field conditions. The pesticide residues found in cultivated fruits from Dakahlia Governorate, Egypt during 2016, using the QuEChERS method prior to analysis by HPLC-DAD. The method validation for extraction and quantitative analysis of diazinon residues in apple fruits using HPLC-DAD, at fortification levels of 0.01, 0.1 and 1.0 mg/kg in apple fruits was used . The obtained results indicated that mean recoveries were ranged from 84.29% to 94.88% with relative standard deviations (RSDs) < 2.30% for HPLC-DAD. In this respect, good linearity was achieved with a determination coefficient (R2) of 0.999 for the 0.01-5 mg/ L concentration range for HPLC-DAD. The limit of quantification (LOQ) of the method was 0.01 mg/ kg. The results suggest that the diazinon dissipation curves followed the first order kinetics and its half-life was 2.03 days in apple. The residues in apple were below the European Union residue limit (MRL) (0.01 mg/kg) after 10 days of the application. [ABSTRACT FROM AUTHOR]