Hydrogen peroxide detection with improved selectivity and sensitivity using constant current potentiometry

In this paper, a potentiometric H2O2 sensor based on a FET structure is presented. The sensor has a redox active gate contact such as Os-polyvinylpyridine (Os-PVP) containing the enzyme horseradish peroxidase (HRP) which has a high sensitivity to H2O2. The basic principle of the sensor is to measure hydrogen peroxide concentration by means of measuring the change in the work function of the electroactive gate of the FET due to its redox reaction with H2O2. A constant current potentiometric mode is used to improve the sensitivity of the sensor. To avoid the influence of ascorbic acid on the sensor, an additional layer of Nafion is mounted on top of the electroactive gate. The influence of the Nafion concentration on the characteristics of the sensor (sensitivity and selectivity) has also been investigated.