Electrochemical performance and electrocatalytic behavior of myoglobin on graphene tube-modified electrode

A new protein biosensing strategy based on a graphene tube (GT)-modified electrode was developed in this article. GT as a fixed material and signal amplifier was loaded on the carbon ionic liquid electrode (CILE) surface, which could provide a suitable environment for myoglobin (Mb) immobilization and promote electron transfer between Mb and the electrode. Fourier-transform infrared spectroscopy (FT-IR) of Mb before and after mixing with GT was checked and showed that the native structure of Mb was maintained. The direct electrochemistry of Mb was investigated with a pair of obtained well-defined and quasireversible redox peaks. The modified electrode (Nafion/Mb/GT/CILE) also showed excellent electrocatalytic activity for the reduction of trichloroacetic acid (TCA) and NaNO2, which could be utilized to determine the concentrations of TCA and NaNO2 with wide detection range and low detection limit. The biosensor was further applied to the detection of a real sample and obtained satisfactory experimental results.