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 x 10(-8) M to 1.2 x 10(-3) M with a correlation coefficient of 0.998, sensitivity of 23.74 mu A/mM and a detection limit of 1 nM at S/N ratio = 3.