Flow injection analysis of ascorbic acid using carriers modified with metal-porphine as oxidative solid catalyses

To investigate one of practical applications of the supports modified with metal-porphines as artificial solid-catalysts, columns into which the supports were packed were supplied to catalytic columns for a flow injection analysis (FIA) system for determination of ascorbic acid (AsA) by the following reactions:AsA+O₂→dehydoroAsA+H₂O₂,H ₂O₂+chromogen→2H₂O+Dye.Among the columns tested, the column containing silica gels modified with Co-tetrakis(carboxyphenyl)porphine catalyzed most rapidly the oxidation reaction of AsA that is accompanied by the formation of hydrogen peroxide. The resulting hydrogen peroxide was determined by FIA system equipped with the column containing glass beads modified with Mn-tetrakis(carboxyphenyl)porphine, which gave a linear calibration curve and large peak-areas of the range corresponding to AsA concentration between 0.2 and 10 μmol/ml. The results indicated that some supports modified with metal-porphine would be applicable to the FIA for AsA as the solid catalyses which function as if the immobilized enzymes.