2.3. Peroxide Sensor

Many oxidoreductase enzymes produce H2O2 as the reaction product. An example is glucose oxidase enzyme that produces H2O2 when glucose reacts with oxygen. H2O2 can be detected by polarography just as with DO sensor. The only difference is that the polarization voltage has to be + 0.7 V instead of - 0.7 V. The circuit given in Fig. 2.14 has to be used instead of the one given in Fig. 2.4 (note that +0.7 V is applied using 78L05 voltage regulator).

Fig. 2.11. Signal amplifier circuit for H2O2 measurement.