A novel hydrogen peroxide sensor based on hemoglobin immobilized PAn-SiO 2/DTAB composite film

A novel hydrogen peroxide (H2O2) sensor based on hemoglobin (Hb) immobilized polyaniline–silica (PAn–SiO2) and dodecyltrimethylammonium bromide (DTAB) composite film modified carbon paste electrode (CPE) was fabricated and the direct electron transfer of immobilized Hb was investigated. On Hb/PAn–SiO2/DTAB/CPE, Hb displayed a fast electron transfer process accompanied with one proton participate in and its electron transfer rate constant which was estimated at 0.94s−1. Thus, the proposed biosensor exhibited a high sensitivity and excellent electrocatalytic activity to the reduction of H2O2. The catalytic reduction current of H2O2 was proportional to H2O2 concentration in the range of 0.09 to 2.8mM with the detection limit of 0.03mM. The apparent Michaelis–Menten constant (Kmapp) of the biosensor was calculated to be 0.275mM, exhibiting high enzymatic activity and affinity. With the characteristics above, the sensor in this paper can be potentially applied in other reactive oxygen species as well.