Flow-injection fluorimetric determination of vitamin K1 based on a photochemical reaction

The sensitizing effect of vitamin K1 on the photo-oxidation of glucose has been used for the determination of the vitamin. The hydrogen peroxide formed in the photochemical reaction reacts with Fe(II) to yield hydroxylradical and this radical is scavenged by benzoic acid to form the fluorescent hydroxybenzoic acids, which are analysed by fluorescence detection. This analytical scheme was adapted to a flow-injection system, which permits the determination of vitamin K1 between 1×10−6 and 1×10−4 M with a throughput of 20 samples h−1 and relative standard deviation between 0.2 and 1%. The applicability of the method was demonstrated by determining vitamin K1 in pharmaceutical preparations and vegetables.