Flow-injection fluorimetric determination of vitamin K-1 based on a photochemical reaction

The sensitizing effect of vitamin K-1 on the photo-oxidation of glucose has been used for the determination of the vitamin. The hydrogen peroxide form ed in the photochemical reaction reacts with Fe(II) to yield hydroxylradica l and this radical is scavenged by benzoic acid to form the fluorescent hyd roxybenzoic acids, which are analysed by fluorescence detection. This analy tical scheme was adapted to a flow-injection system, which permits the dete rmination of vitamin K-1 between 1 x 10(-6) and 1 x 10(-4) M with a through put of 20 samples h(-1) and relative standard deviation between 0.2 and 1%. The applicability of the method was demonstrated by determining vitamin K- 1 in pharmaceutical preparations and vegetables. (C) 1999 Elsevier Science B.V. All rights reserved.