Simultaneous Determination of Fluoxastrobin and Tebuconazole in Cucumber and Soil Based on Solid-Phase Extraction and LC-MS/MS Method

Based on aqueous acetonitrile extraction (AAE) and solid-phase extraction (SPE) pretreatments, an analytical method was first introduced for the simultaneous determination of E/Z-fluoxastrobins and tebuconazole in cucumber and soil. The method validation obtained satisfactory results in terms of linearity, matrix effect (− 17.7–2.9%), fortified recovery (78.4–108.0%), precision (1.1–11.9%), and sensitivity (the limits of quantification were 5 μg/kg). During application of the method, the recommended method was used to estimate the dissipation and residues of fluoxastrobin and tebuconazole in cucumber and soil in field tests. The results showed that the half-lives of fluoxastrobin and tebuconazole were 6.5–8.3 days in cucumber and 11.6–12.2 days in soil. In the terminal residue experiment, the residues of fluoxastrobin and tebuconazole were 33–389 and 35–522 μg/kg in cucumber, respectively. Referencing the maximum residue limits (MRLs) of fluoxastrobin (0.5 mg/kg, US Environmental Protection Agency) and tebuconazole (1.0 mg/kg, China), 1 day is recommended as the preharvest interval for the application of fluoxastrobin and tebuconazole in cucumber.