Residue, dissipation, and safety evaluation of etoxazole and pyridaben in Goji berry under open-field conditions in the China's Qinghai-Tibet Plateau.

Abstract

The dissipation and residual levels of etoxazole and pyridaben in Goji berry under open field conditions were determined by using GC-NPD (gas chromatography with nitrogen and phosphorus detector) with modified QuEChERS method. At fortification levels of 0.01, 1, and 5mg/kg in Goji berry, it was shown that recoveries were ranged from 80.40 to 100.9% with relative standard deviation of the method (RSD) for repeatability ranged from 2.20 to 4.25%. The limit of quantification (LOQ) of the method was 0.01mg/kg. The dissipation rates of etoxazole and pyridaben were described by using first-order kinetics and its half-life, as they are 7.13days, 5.77days, and 5.99days (etoxazole) and 1.02day, 0.67day, 1.02day (pyridaben). The terminal residues of etoxazole and pyridaben were below the European maximum residue limit (MRL, 0.1mg/kg) in Goji berry when measured 7days after the final application, which suggested that the use of these insecticides was safe for humans. This study would help in providing the basic information for developing regulation to guard a safe use of etoxazole and pyridaben in Goji berry and prevent health problem from consumers.