Improved method for determination of abamectin and ivermectin in cattle plasma

Abstract

A liquid chromatographic (LC) method was developed for determination of abamectin (ABM) and ivermectin (IVM) in cattle plasma. The sample was extracted with acetonitrile and cleaned up on an alumina column. After conversion to stable fluorescent derivative with trifluoroacetic anhydride and N-methylimidazole, the sample was analyzed by LC with fluorescence detection (Ex 365 nm and Em 475 nm). Doramectin was used as an internal standard. Recoveries ranged from 91.2 to 100.7% for IVM and from 87.0 to 98.7% for ABM, with 1-50 ng/mL fortified samples. The coefficients of variation were <10.1 %. The limit of detection was 0.02 ng/mL for ABM and IVM in 1.0 mL samples.