Determination of Avermectin Residue in Cucumber and Pear by Reversed-Phase High Performance Liquid Chromatography

A reversed-phase high performance liquid chromatography(RP-HPLC) method for determination of avermectin in vegetable and fruit was developed.Cucumber and pear samples were extracted by methanol,and further extracted with dichloromethane by liquid-liquid extraction.The extract was cleaned-up with florisil cartridge,the residue was redissolved with methanol.The analysis was carried out by using C18 reverse phase column(25 cm×۴.۶ mm,10 μm).The mobile phase was methanol-water(V/V=90/10),with flow rate of 1.0 mL·min-1.Avermectin was detected at 245 nm and quantified by external standard method.Avermectin showed good linear regression in the range of 0.05～۵.۰۰ mg·L-1 in sample solution(r=1.000 0).The average recoveries ranged from 82.99% to 92.23%,with relative standard deviations 2.31%～۴.۱۵%.The detection limit of avermectin in vegetable and fruit was 0.001 mg·kg-1.