The electrochemical behavior of iron(III) incorporated in zeolite Y-modified electrode and the catalytic oxidation of ascorbic acid

A new method is developed for the catalytic oxidation of ascorbic acid (AA) at a graphite-zeolite-modified electrode doped with iron(III) (Fe3+Y/ZCME) , in which iron(III) exchanged in zeolite Y can act as catalyst to oxidize PLA. First, the electrochemical behavior of iron(III) incorporated in the z eolite Y-modified electrode was studied. The results illustrate that diffus ion controls the ferric/ferrous redox process at the Fe3+Y/ZCME. The anodic current of this process increases with the supporting electrolyte concentr ation of non-size-excluded cation and was suppressed when using size-exclud ed cation. Second, the catalytic oxidation of AA was explored at Fe3+Y/ZCME . With constant potential amperometric measurements optimal conditions for AA determination were obtained. The working potential was 0.55 V (vs. SCE); the supporting electrolyte was 0.1 M KNO3 or 0.05 M Na2HPO4-KH2PO4 buffer solution (pH 6.8). The response current exhibits a linear relationship with the concentration of AA over the range of 1.58 x 10(-6)-2.15 x 10(-2) M. W hen samples of urine, and fruit were analyzed with Fe3+Y/ZCME, we obtained AA recovery of 98-102%, and a relative standard deviation lower than 3%. Me anwhile, interferences from other ions and organic substances were examined .