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 mu L/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 mu M H2O2, respectively. The sensor can measure reliably between 1 and 200 mu M H2O2. The concentration range can be extended to 1000 mu M H2O2 by exchanging the O2 sensor. Interfering species (NaONOO, NaOCl, tBuOOH, 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.

Automated summary

An optical hydrogen peroxide sensor based on catalytic degradation and the detection of produced oxygen is presented. The sensor offers higher resolution and better sensitivity at lower H2O2 concentrations. By removing O2 from the sample solution, a more sensitive O2 sensor can be used for measurement. The sensor has been successfully applied in a flow-through cell to measure H2O2 concentration in different flow rates.