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.