Potential application of hemoglobin as an alternative to peroxidase in a phenol biosensor

This work describes a new amperometric biosensor for detecting phenolic compounds. The sensor was designed by immobilizing Hemoglobin (Hb) in a sol-gel matrix onto a carbon electrode. Using the peroxidase activity of Hb, the phenolic compound can be reduced in the presence of H2O2. The biosensor's performance in phenolic compound detection was based on mediated electron transfer by Hb. The direct electron transfer of Hb can be avoided by use of the sol-gel matrix. The proposed biosensor presents a very sensitive response for phenolic compounds at an applied potential of 0.0 mV vs. Ag/AgCl. The parameters of the fabrication process for the electrode were optimized. Experimental conditions influencing the biosensor performance, such as pH and potential, were investigated and assessed. Various types of phenolic compounds were detected. Among them, using the optimized conditions, a linearity for the detection of the phenol was observed from 5 mu M to 50 mu M. Biosensor response levels after 30 days were at more than 80% of their initial response readings level. The response time of the biosensor was about 10 s. (C) 2007 Elsevier B.V. All rights reserved.