Fluorometric Determination of Hydrogen Peroxide in Natural Water Samples by Flow Injection Analysis with a Reaction Column of Peroxidase Immobilized onto Chitosan Beads

It was found that a FIA system with an immobilized enzyme reaction column could be utilized for the determinations of hydrogen peroxide in some water samples, such as rain water and tap water. A column was packed with chitosan beads immobilizing horseradish peroxidase. Under the recommended conditions, it took 5 min for each assay, and the detection limit, which was defined as a signal-to-noise ratio of 3, was 3.0 ng dm−3 of hydrogen peroxide. The relative standard deviation at 1.0 mg dm−3 of hydrogen peroxide was 1.5% (n=20). There was no interference from some coexisting substances having a low oxidation-reduction ability or not; therefore, a standard addition method could be applied to rain water and tap water samples. From such results, it has become clear that the proposed FIA system can be applied to the determination of hydrogen peroxide in water samples, and that the system is suitable for routine analysis in environmental observations.