Analytical Sciences

Abstract − Analytical Sciences, 23(1), 71 (2007).

Carbon Felt-based Bioelectrocatalytic Flow Detectors: Highly Sensitive Amperometric Determination of Hydrogen Peroxide Using Adsorbed Peroxidase and Thionine
Yasushi HASEBE, Ryosuke IMAI, Masaki HIRONO, and Shunichi UCHIYAMA
Department of Applied Chemistry, Faculty of Engineering, Saitama Institute of Technology, 1690 Fusaiji, Fukaya, Saitama 369-0293, Japan
Horseradish peroxidase (HRP) and thionine (TN) were co-adsorbed onto a porous carbon felt (CF), and the resulting HRP and TN-adsorbed CF (HRP-TN-CF) was successfully used as a working electrode unit of a novel bioelectrocatalytic flow detector for a highly sensitive amperometric determination of hydrogen peroxide (H2O2). Co-adsorbed TN was essential to enhance the cathodic peak current of H2O2, and the current responses of the HRP-TN-CF-based detector were much larger than those of the HRP-CF-based detector (without TN). When air-saturated 0.1 M phosphate buffer (pH 7.0) was used as a carrier at a flow rate of 3.9 ml/min, cathodic peak currents of H2O2 (sample injection volume, 200 µl) obtained at an applied potential of 0 V (vs. Ag/AgCl) increased linearly up to 50 µM with a detection limit of 0.1 µM. Repetitive 100 sample injection of 100 µM H2O2 induced no serious current decrease, and RSD was 0.41 to 1.21% (n = 100). The HRP-TN-CF retained 42% of its original activity after 8 days of storage in 0.1 M phosphate buffer at 4°C.