Determination of ethofenprox residue in cabbage and soil by UPLC-MS

A UPLC-MS method for determination of ethofenprox residue in cabbage and soil has been established.The mean recoveries of the method varied from 80.3% to 105.5% and the relative standard deviation (RSD) was less than 6.9%,at three spiked levels(0.02,0.20 and 2.00 mg/kg).The limit of quantification of ethofenprox in cabbage and soil was 0.02 mg/kg.The method was characterized by simplicity,higher sensitivity and accuracy.This method was applied to study the residue and decline dynamics of ethofenprox in Beijing,Hangzhou and Kunming.Results of decline study showed that the half-life of ethofenprox in cabbage and soil were 1.9 to 2.1 d and 14 to 16 d,respectively.When sprayed for 3 to 4 successive times at application dosage of 60 or 90 g(ai)/ha at interval time of 7 d,the final residue of ethofenprox in cabbage and soil were not detected from 7,14,21 d after the last spray.