Determination of Phylloquinone-2, 3-epoxide and Menaquinone-4-2, 3-epoxide in Biological Materials by High Performance Liquid Chromatography and Fluorometric Reaction Detection

Abstract

A high performance liquid chromatographic method was developed for the simultaneous determination of vitamin K and vitamin K oxide in biological materials. The method involves n-hexane extraction of plasma or liver homogenate and reversed phase separation on Nucleosil[○!R] C₁₈ with a mobile phase of methanol-ethanol (7 : 3, v/v) followed by fluorometric detection of the reaction products with NaHSO₃-HCl and NaBH₃CN. Minimum detectable quantity was 2 ng for phylloquinone and menaquinone-4, and 3 ng for phylloquinone oxide and menaquinone-4 oxide, respectively. This method is simpler and more specific than the conventional methods for the determination of vitamin K oxide.