Rapid and Accurate Simultaneous Determination of Abamectin and Ivermectin in Bovine Milk by High Performance Liquid Chromatography with Fluorescence Detection

An analytical method using high performance liquid chromatography with fluorescence detection for the simultaneous determination of abamectin and ivermectin in bovine milk was developed and validated. The best recovery results were achieved by using acetonitrile for extraction of the compounds followed by solid phase extraction in cartridges containing C-18 for the purification of the extract. Pre-column derivatization was accomplished with N-methylimidazole and trifluoroacetic anhydride. The method limit of detection (LOD) values for abamectin and ivermectin were 0.10 and 0.14 mu g L-1 and the limit of quantification (LOQ) values were 0.18 and 0.36 mu g L-1, respectively. The recoveries were from 75 to 101%, with RSD values lower than 10%. The LOD and LOQ values are lower than the maximum residue limits (MRLs) in milk established by Codex Alimentarius, European Union and the Brazilian legislation.