An Amperometric Sensor for Nanomolar Detection of Hydrogen Peroxide Based on Encapsulation of Horseradish Peroxidase in Thymol Blue-Ormosil Composite

An amperometric biosensor based on horseradish peroxidase and thymol blue-organically modified sol–gel glass composite has been fabricated for the determination of H₂O₂. we are for the first time reporting electrochemistry of thymol blue encapsulated within organically modified sol–gel glass. the biosensor has been characterized by electrochemical and amperometric measurements. the biosensor shows fast response with minimum interference. under the optimized experimental conditions, H₂O₂ could be determined in a linear calibration range from 1.0 × 10^–8 M to 1.2 × 10^–3 M with a correlation coefficient of 0.998, sensitivity of 23.74 μA/mM and a detection limit of 1 nM at S/N ratio = 3.