Biosensor potentiometric hydrogen peroxide

Redox-based biosensors. Noble metals (platinum and gold) and carbon electrodes may be functionalized by oxidation procedures leaving oxidized surfaces. In fact, the potentiometric response of solid electrodes is strongly determined by the surface state [147]. Various enzymes have been attached (whether physically or chemically) to these pretreated electrodes and the biocatalytic reaction that takes place at the sensor tip may create potential shifts proportional to the amount of reactant present. Some products of the enzyme reaction that may alter the redox state of the surface e.g. hydrogen peroxide and protons) are suspected to play a major role in the observed potential shifts [147]. 

Fig. 17.11. (a) Potentiometric biosensor based on pH electrode (b) Poten-tiometric biosensor based on gas electrode (c) Oxygen electrode determination of oxygen (d) Oxygen electrode determination of hydrogen peroxide (from Ref. 

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