Hydrogen peroxide determination based on a glassy carbon electrode covered with polyion complex membrane containing peroxidase and mediator

Peroxidase (POD)/ferrocene co-immobilized polyion complex membrane was prepared on a glassy carbon electrode by dropping, and then drying, the enzyme solution, ferrocene dispersion, poly-l-lysine and polystyrene sulfonate solutions on the surface. The current response to hydrogen peroxide on the electrode was measured in a phosphate buffer (pH 6.5) solution. The response time was found to be short (15 s). The calibration curve of hydrogen peroxide was obtained. The response to hydrogen peroxide on the electrode was found to be linear to its concentration up to 10 μM, and the lower detection limit was 0.5 μM (S/N=5). The results indicate that a sensitive detection of hydrogen peroxide was accomplished. Influence of an electrochemical interfering material on the current response was examined. The ratio of the current response to hydrogen peroxide/l-ascorbate was found to be ca. 10 when these substances of the same concentration (10 μM) were injected to the test solution. Highly-sensitive biosensors were obtained by immobilizing oxidases on the surface of the POD-based electrode.