Optical hydrogen peroxide sensor for measurements in flow

An optical hydrogen peroxide (H2O2) sensor is presented. The sensor is based on catalytic degradation of H2O2 and the detection of produced oxygen (O2) with a phosphorescent sensor. A novel aspect of the sensor is removal O2 from the analyte solution in flow. This allows the use of a more sensitive O2 sensor. Thereby, a better resolution at lower H2O2 concentrations is achieved. Sensor spots are integrated in a flow-through cell, and H2O2 is measured in flow between 10 and 80 µL/min. The catalytic activities of previously reported catalyst are tested. RuO2 and silica supported platinum nanoparticles are applied in the sensor with limit of detections of 0.16 and 0.17 µM H2O2, respectively. The sensor can measure reliably between 1 and 200 µM H2O2. The concentration range can be extended to 1000 µM H2O2 by exchanging the O2 sensor. Interfering species (NaONOO, NaOCl, t-BuOOH, and ascorbic acid) are tested and show only minor cross-sensitivities. The sensor is applied at-line in a model batch reactor with glucose oxidase to showcase production of H2O2 from glucose. © 2023 The Authors