Amperometric biosensors for sensing of hydrogen peroxide based on electron transfer between horseradish peroxidase and ferrocene as a mediator

A non-conducting polymer film of 3-aminophenol, in which horseradish peroxidase was immobilized, has been prepared on a carbon paste electrode containing both ferrocene as a mediator and horseradish peroxidase by the electrochemical polymerization. The response currents of this hydrogen peroxide sensor linearly increased with increasing the concentration of hydrogen peroxide of 0.6 to 20 mu mol dm(-3); the straight line had a slope equal to 10.1 mA mol(-1) dm(3) (r = 0.999). This hydrogen peroxide sensor may be available for the fabrication of other biosensors, e.g. glucose and cholesterol sensors, which are not influenced by easily oxidizable species, L-ascorbic acid and uric acid.