Simultaneous determination of fat-soluble vitamins A, D and E and pro-vitamin D2 in animal feeds by one-step extraction and high-performance liquid chromatography analysis.

Traditionally, alkaline saponification for the extraction of vitamins and step-wise HPLC analyses have been widely used for analysis of fat-soluble vitamins in animal feeds. The objective of present study was to develop an analytical method using one-step extraction and simultaneous determination of the vitamins A, D and E and pro-vitamin D2 in animals feeds b HPLC. Various analytical conditions were tested which included sample particle size extraction solvents, the ratio of solvent to sample, extraction approach, extraction time, N2 protection, prepurification with Sep-Pak cartridge and detection wavelength. The accuracy of the developed method has been proven by comparison with the AOAC method. The reproducibility of the developed method has been substantiated by repeated recovery experiments. The detection limit for the four vitamins was 10 ng/g of feed sample. One of the important properties of the present method is rapidity and ease of use.