Exploration and quantification of ascorbate affecting peroxidase-catalyzed chromogenic reactions with a recirculating-flow catalysis detection system.

The use of a recirculating-flow catalysis detection system (RFCD) explored competition and the influence of ascorbic acid (AsA) in peroxidase (POD)-catalyzed reactions. The study identified that AsA is neither the inhibitor of POD nor could directly deplete H2O2; it directly reacts with chromogenic products to form colorless intermediates, which can react with H2O2 to again rapidly re-generate the chromogenic products. If using the reactions (trinder reactions or enzyme-linked reactions) to determine POD activity (EPOD), substrates or analytes, the interference of concomitant AsA should be removed and the conclusions have significance for oxidase/POD catalyzed reactions. In addition, the RFCD system was also used to simultaneously determine EPOD and AsA.