An amperometric new methylene blue N-mediating sensor for hydrogen peroxide based on regenerated silk fibroin as an immobilization matrix for peroxidase

A simple and effective procedure was described for the immobilization of peroxidase in regenerated silk. fibroin membrane prepared from waste silk. The membranes of regenerated silk fibroin with or without peroxidase, before or after the ethanol treatment, were characterized by ir spectra. An amperometric H2O2 sensor, based on the immobilized peroxidase in regenerated silk fibroin membrane, in the use of new methylene blue N as an electron transfer mediator, was fabricated. The characteristics of the sensor with respect to linearity, response time, effect of pH and temperature, stability, and reproducibility were investigated. Dependences of Michaelis-Menten constant K-M(app) on the concentration of the mediator, and the applied potential were also studied and the results were presented. The sensor was highly sensitive to H2O2 with a detection limit of 1.0 x 10(-7) M and with response time of less than 40 s. (C) 1996 Academic Press, Inc.