Hydrogen Peroxide Biosensor Based on Cellulose Diacetate-Ionic Liquid Film Immobilizing Myoglobin

Myoglobin (Mb) was immobilized on the surface of a glassy carbon electrode using a composite membrane of cellulose diacetate (CDA) and the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4). Spectroscopic analysis of the CDA-[bmim]BF4-Mb film showed that Mb could retain its natural structure and bioactivity. The conductivity of the modified electrode was greatly improved due to the doping with the ionic liquid, which facilitated electronic transfer of the CDA-[bmim]BF4-Mb membrane. Further experiments showed that the Mb-modified electrode possessed an electrocatalytic activity for the reduction of hydrogen peroxide (H2O2). The catalytic peak current was linear with reference to H2O2 concentrations in the range of 5.0-100 μM, with a detection limit of 2.0 μM. The apparent Michaelis-Menten constant (Km) was estimated to be 1.758 × 10−4 M.