Residues of the Acaricides Abamectin, Hexythiazox, and Spiromesifen in Eggplant ( Solanum melongena L.) Fruits Grown under Field Conditions in Najran, Saudi Arabia

The dissipation profiles of the acaricides abamectin, hexythiazox, and spiromesifen in the fruits of eggplant ( Solanum melongena L.) grown under field conditions in Najran, Saudi Arabia, were studied. Extraction was performed with acetonitrile, and UPLC-MS/MS was used for quantification. Instead of conventional adsorbents, a 2-fold dilution of the sample extract quickly and efficiently reduced interfering co-extracts and matrix effects. The method was successfully validated according to EU regulations. The limit of quantification was set at 5 µg/kg for hexythiazox and spiromesifen and 20 µg/kg for abamectin. The mean recoveries and relative standard deviations were 88.6–98.7% and 5.2–12.4%, respectively. The method precision was evaluated at the LOQ level for each analyte and ranged from 6.7 to 15.7%, with good trueness (recovery) ranging from 85.7 to 97.2%. The matrix effect ranged from −2.2% to −4.6%, indicating negligible signal suppression. First-order kinetics were used to characterize the dissipation rates of abamectin, hexythiazox, and spiromesifen with half-lives (t 1/2 ) of 2.11–2.42, 2.3–2.73, and 1.31–1.47 days, respectively, using the authorized and double authorized doses. Terminal residues were 0.028–0.331 mg/kg, 0.019–0.592 mg/kg, and 0.044–0.408 mg/kg, respectively, at 3, 7, and 10 days after the second treatment. According to the risk assessment results, the percentage of chronic dietary risk quotient was <100, meaning that abamectin, hexythiazox, and spiromesifen are not considered a risk to human health. The preharvest interval (PHI) should be 7, 7, and 3 days, respectively, if the authorized dose is used, and 10, 10, and 3 days, respectively, if double the authorized dose is used. The current study can be a helpful resource for the responsible and safe use of the tested acaricides on eggplant fruits.