Photokinetic determination of riboflavin and riboflavin 5′-phosphate using flow injection analysis and chemiluminescence detection

Abstract

A flow injection procedure for the photochemical determination of riboflavin and riboflavin 5′-phosphate has been developed. The method is based on the photo-reduction of both compounds by ethylenediaminetetraacetic acid, the rate of which is a linear function of their concentration at very low levels. The rate of these photochemical reactions was monitored by making use of the chemiluminescent hydrogen peroxide–luminol reaction and determining the hydrogen peroxide reduced by the 1,5-dihydro forms of these flavins, which are generated during the photochemical process. Linear calibration graphs were obtained between 1 × 10^–7 and 3 × 10^–6 mol l^–1. The method has been successfully applied to the determination of B₂ vitamers in pharmaceutical preparations, foods and animal tissues.