Electrochemistry of myoglobin in Nafion and multi-walled carbon nanotubes modified carbon ionic liquid electrode

The direct electrochemistry of myoglobin (Mb) entrapped in the Nafion film on a multi-walled carbon nanotubes (MWCNTs) modified carbon ionic liquid electrode (CILE) had been investigated in this paper. By using a hydrophilic ionic liquid of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) as the modifier, a high-performance basal electrode was fabricated and further modified by MWCNTs, Mb and Nafion by a step-by-step casting method. Spectroscopic results indicated that the Mb molecule on the surface of MWCNTs/CILE retained its native structure. Cyclic voltammetric results showed that a pair of well-defined quasi-reversible redox peaks appeared in the pH 7.0 phosphate buffer solution (PBS), which was attributed to the direct electron transfer of Mb heme Fe(III)/Fe(II) redox couples with the modified electrode. The Nafion/Mb/MWCNTs/CILE gave excellent electrocatalytic activity towards different substrates including trichloroacetic acid (TCA), hydrogen peroxide (H2O2) and sodium nitrite (NaNO2).