High Performance Liquid Chromatographic Method for the Assay of Tebufenozide Insecticide in Suspension Formulations

A simple, reliable, and robust liquid chromatographic method is described to separate and quantify tebufenozide insecticide in suspension concentrates. The analyte was extracted with acetonitrile and partitioned with hexane to remove lipoid and other nonpolar additives in the formulation to improve selectivity and specificity. The concentration of the insecticide in the polar phase was adjusted volumetrically and analysed using an RP-8, 10-mm, 200 x 4.6 mm i.d. bonded phase column, with diode-array detection at 236 nm and 50% water/50% acetonitrile-dioxane (4:1, v/v), as the mobile phase. The linear concentration range, limit of detection, and limit of quantification for the insecticide were 5 to 500 ng (in 40-mgL injection volume), 1.0 ng and 5.0 ng, respectively. Triplicate analysis of 3 lots of commercial suspension concentrates gave values that were agreeable with those given on the labels. The method, with necessary modifications, could be extended and used routinely as a quality control method in the analysis of different types of tebufenozide formulations.