2.54 - Detection of Hydrogen Peroxide and Organic Peroxides in Flow Injection Based on Peroxidase Modified Carbon Fiber Microelectrodes

Abstract

This chapter discusses a study focusing on the detection of hydrogen peroxide and organic peroxides in flow injection based on peroxidase modified carbon fiber microelectrodes. Mediatorless amperometric microbiosensors can be constructed by immobilizing various peroxidases (horseradish peroxidase (HRP), fungal peroxidase from Arthromyces ramosus (ARP)) on carbon fibers. Several types of carbon fibers were tested. As the electron transfer between the electrode and the active site of the immobilized enzyme appears to be a direct one, the nature (modulus) of the tested fibers was found to have a decisive role on the performance of the resulting microelectrodes. The high modulus type graphite fibers were found to be the most suitable for microsensor construction, yielding the highest current signals and the lowest detection limits. Linear current responses were recorded over 2 decades (20–2500 mM) both for hydrogen peroxide and organic peroxides. The detection limits of the electrodes were calculated as twice the signal to noise ratio. As low detection limits as 0.3 μM for hydrogen peroxide, 6 μM for cumol hydroperoxide, and 20 μM for 2-butanone peroxide characterized the microdetectors. The electrodes were characterized of rapid response times.