Catalytic activity of thiacalix[4]arenetetrasulfonate metal complexes on modified anion-exchangers for ascorbic acid oxidation

Abstract

The catalysis of ascorbic acid (AsA) oxidation by anion-exchangers modified with metal complexes of thiacalix[4]arenetetrasulfonate (Me-TCAS[4] A-500, Me=Mn3+, Fe3+, Co3+, Ce 4+, Cu2+, Zn2+, Ni2+, and H 2) were investigated. Me-TCAS[4]A-500 (Me=Mn3+, Fe3+, Ce4+, and Cu2+) all exhibited the ability to catalyze the oxidative reaction of AsA to dehydroascorbic acid. However, in the presence of high concentrations of AsA, only Cu 2+-TCAS[4]A-500was capable of complete oxidation of the acid. Moreover, after six repeat uses, Cu2+-TCAS[4]A-500 maintained high and relatively constant catalytic activity. Prior treatment of glucose solutions with Cu2+-TCAS[4]A-500even in the presence of high AsA concentrations, enabled the satisfactory determination of glucose without interference by AsA. Cu2+-TCAS[4]A-500 will therefore be applicable as an artificial substitute for ascorbate oxidase, and may be useful as a means to eliminate AsA interference during the analysis of vital compounds such as glucose and uric acid. © 2013 The Pharmaceutical Society of Japan.