Residue Dissipation\nDynamics and Dietary Risk Assessment\nof Kasugamycin, Oxine-Copper, Dimethomorph, and Pyraclostrobin in\nCucumber

In recent years, pesticides have\nbeen overapplied to prevent and\ncontrol cucumber diseases, and high pesticide residues on cucumbers\nhave become a growing concern. Therefore, the establishment of a rapid\nand reliable method for the detection of pesticide residues is particularly\nrequired to ensure the health of humans and livestock. This study\noptimized the determination method of pesticide residues in cucumber\nusing a QuEchERS pretreatment combined with an ultrahigh performance\nliquid chromatography-tandem mass spectrometry. The optimized method\nachieved a spike recovery rate of 79.1–103.3% for the kasugamycin,\noxine-copper, dimethomorph, and pyraclostrobin in cucumber, and the\nlimit of quantification was 0.01 mg/kg. The optimized method was used\nto detect there residues in 12 regions. The dissipation half-lives\nof oxine-copper, dimethomorph, and pyraclostrobin were 1.64–2.19,\n1.15, and 1.20–1.27 days, respectively. The final residue levels\nof these pesticides were all below the maximum residue limit. The\ndietary risk assessment showed that the daily intake of kasugamycin,\noxine-copper, dimethomorph, and pyraclostrobin accounted for 0.7,\n35.7, 23.7, and 20.5% of the daily allowable intake, respectively,\nwhich were all within acceptable ranges. This indicates that under\nthe ecological conditions in China, these pesticides are safe under\ngood agricultural practices. This study provides guidance for the\ncomprehensive evaluation and scientific use of fungicide residues\nin the cultivation of vegetables cash crops such as cucumber.