Ivermectin in reindeer feces: determination by HPLC.

An assay method for the determination of ivermectin in reindeer feces was developed. Ivermectin was quantified by high-performance liquid chromatography and fluorescence detection after extraction (acetone, isooctane), cleanup (C-18 solid-phase extraction column), and derivatization to a fluorescent derivative using N-methylimidazole and trifluoroacetic anhydride. Concentration calculations were based on calibration lines found from analyses of standards prepared in feces. Abamectin was used as internal standard. Ivermectin was determined over a wide concentration range in a single sample preparation and HPLC run for each sample. The recovery from fortified samples was greater than 95% over the concentration range 5-2000 ng/g wet weight feces.