PHOTOCHEMICAL METHOD FOR THE DETERMINATION OF HYDROGEN-PEROXIDE AND GLUCOSE

Reduction of hydrogen peroxide was achieved with leuco-phloxin in the presence of haematin. The leuco dye was generated through the photochemical reaction between phloxin and ethylenediaminetetraacetic acid. The method involves measuring the time to reach the end-point of the photochemical titration, i.e., the photolysis time necessary for the total reduction of the peroxide. The method can be extended to the determination of substrate-enzyme systems that produce hydrogen peroxide, e.g., glucose-glucose oxidase. The assay is linear between 0.12 and 4.61 mug cm-3 for hydrogen peroxide (r = 0.9992) and between 3.99 and 43.2 mug cm-3 for glucose (r = 0.9989). The detection limit, defined as three times the standard deviation of the reagent blank, was 0.03 mug cm-3 for hydrogen peroxide and 1.0 mug cm-3 for glucose.