Residual Pattern of Acequinocyl and Hydroxyacequinocyl in Perilla Leaf Grown under Greenhouse Conditions using Ultra Performance Liquid Chromatography-Photo Diode Array Detector with Tandem Mass Confirmation

Persistence and degradation behaviors of acequinocyl and hydroxyacequinocyl were determined in perilla leaf grown under greenhouse conditions. Acequinocyl (15%, SC) was sprayed on perilla leaf at the recommended dose rate of 37.5 g/250 L water/10a with single and double dose applications. Leaf samples were collected randomly at 0 (2 h after application), 1, 3, 5, and 7 days post-application from two different plots. The samples were extracted with acetonitrile, purified through a solid phase extraction procedure, and analyzed via ultra performance liquid chromatography coupled with photo diode array detector (UPLC-PDA). Residues were confirmed via liquid chromatography tandem mass spectrometry (LC-MS/MS) in positive-ion electrospray ionization (ESI+) mode. Calibration curves were linear over the concentration ranges for the analytes with r(2) >= 0.992. The limits of detection and quantification were 0.05 and 0.165 mg/kg for both acequinocyl and hydroxyacequinocyl. The method was validated in triplicate at two fortification concentrations in the matrix. Good recoveries were observed for the target analytes, ranging between 94.95 and 113.26% with relative standard deviations less than 6%. The rates of disappearance of total acequinocyl on perilla leaf for single and double doses were described as first-order kinetics with half-lives of 2.8 and 3.1-days, respectively.