Residue distribution, safety evaluation, processing factor and dissipation kinetics of bifenthrin and ethion in date fruits

Gas chromatography with ion trap mass spectrometry was used to simultaneously analyses bifenthrin and ethion residues in date fruits after acetonitrile extraction and dispersive solid phase extraction for clean-up. The method was validated in line with the SANTE/11813/2017 guideline with performance criteria including the linearity range, repeatability, intermediate reproducibility, matrix effect, recovery, and limit of quantitation. Attractive advances results include: (1) lower quantitation limit of 6.9 and 5.8 μg/kg; (2) the recoveries were between 91.61 and 98.84%, and the corresponding relative standard deviations (RSDs) were lower than 11.7%; (3) excellent repeatability RSDr of lower than 10.3 μg/kg, and intermediate reproducibility RSDR of lower than 15.6 μg/kg, Furthermore, the method is fast and simple. After validation, the developed method was successfully applied for the determination of the dissipation kinetics of the bifenthrin and ethion in date fruits over 45 days under field conditions of Saudi Arabia. The results showed that the dissipation kinetics of bifenthrin and ethion can be described by a first-order kinetics model with a half-life (t0.5) of 1.92 and 2.43 days for bifenthrin and 2.2 and 2.59 days for ethion, at the low and high recommended application rates, respectively. For safe consumption of dates, waiting periods of 12 and 28 days for bifenthrin and 18 and 38 days for ethion are suggested. A total of 600 date samples were collected from the largest market in the world in Qassim Province, Buraydah City, in 2017-2018. A risk assessment of the residues was performed by calculating the risk quotients for children and adults in Saudi Arabia. The high consumption of dates by children may have hazards. The processing factors for washing with tap water, and washing plus boiling (date syrup production) showed that washing had little effect on residue reduction compared with washing plus boiling.