Determination of ivermectin in feeds by high-performance liquid chromatography
A direct high-performance liquid chromatographic method has been developed for the determination of ivermectin in feeds over the concentration range 50–500 mg kg–1. Sample preparation is based upon extraction into methanol and separation of interferences on a gravity-fed alumina (activity III) column in advance of introduction into a standard reversed-phase chromatographic system. Experiments are described to document the efficiency of this sample preparation scheme and the chemical yield of the analyte through the process. The method has been applied to three types of feed samples with an accuracy of ±3.4% mean relative error and a relative standard deviation (precision) of <3%. It has a lower limit of detection with a signal to noise ratio 2 : 1 of 6.0 mg kg–1 of ivermectin.