Selective monitoring of the hydrogen peroxide signal in the presence of ascorbic acid. Part II: Preliminary practical realization of applying immittance spectroscopy

The experimental realization of implementing an AC immittance technique for the selective amperometric monitoring of hydrogen peroxide in the presence of ascorbic acid on a single unmodified electrode is presented. The experi mental parameters selected to achieve selectivity for peroxide were based u pon the predictions of the theoretical models presented earlier [13] and th e manipulation of experimentally available parameters. Differences in kinet ics between the desired and interfering electrooxidation processes were exp loited hy the AC technique to yield a strong peroxide signal and a negligib le ascorbic acid signal to overcome a significant limitation of conventiona l AC amperometry. A "normal" molar signal ratio for the DC amperometric mea surement of 0.5:1.0 for ascorbic acid: hydrogen peroxide on Pt, was reduced to 0.03:1.0 using the proposed AC method in a model test solution.