An improved method for analysis of cholecalciferol-treated baits

Abstract

A liquid extraction method is described that permits rapid determination of cholecalciferol (D3) in rodenticidal grain baits. Purified D3 was incubated for various time periods to produce pre-D3. Response ratios (concentration/detector response) for various concentrations of pre-D3 and D3 in solutions permitted generation of a correction factor for direct quantitation of pre-D3 in solutions with a pure D3 standard. The method has equal precision and accuracy, yet is simpler and less time consuming and requires less solvents than widely accepted methods for extracting D3 from grain baits. Recoveries from control oat baits fortified at 0.05 and 0.75 wt % were 100.9 and 98%, respectively. A standard curve for concentrations ranging from 6.4 to 204 μg/mL had an r2 of 0.9999 and an intercept of zero and was linear and proportional. The method limit of detection was 2.0 x 10-4 wt % D3.