Analysis of fat-soluble vitamins. XXVIII. High performance liquid chromatographic determination of vitamin D in pet foods and feeds: collaborative study.
A high performance liquid chromatographic (HPLC) method for vitamin D in pet foods and feeds at low concentrations (2-8 IU/g = 50-200 ppb) was studied collaboratively. The procedure consists of the following purification steps: saponification, extraction of the unsaponifiable fraction, chromatography on alumina, cleanup on reverse phase HPLC, and quantitation with straight phase HPLC. The original method, developed by Knapstein, was simplified by deleting the quantitative TLC step. Six coded samples were distributed to 31 laboratories, along with a known sample containing 15 IU/g to allow practice of the rather complicated procedure. Eighteen collaborators returned their results. Results for the spiked samples show good recovery. The estimates of repeatability and reproducibility are 0.96 and 2.2 IU/g for spiked samples and 1.5 and 3.1 IU/g for commercial samples, respectively, which are considered acceptable for these low concentrations. The method has been adopted official first action.
D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D000829:Animals, Domestic; D002415:Cats; D002645:Chickens; D002851:Chromatography, High Pressure Liquid; D008055:Lipids; D012995:Solubility; D014807:Vitamin D / Q000032:analysis*
D008055:Lipids; D014807:Vitamin D