Nafion-ZrO2 nanoparticle-ionic liquid nanobiocomposite for the direct electrochemistry of myoglobin

A nanobiocomposite was perpared by mixing zirconia nanoparticle with ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate and Nafion together, which was further used to immobilize myoglobin (Mb) on the surface of carbon ionic liquid electrode. UV-Vis and FT-IR spectroscopic results confirmed that Mb remained its native structure in the nanobiocomposite material. Cyclic voltammetric results showed that a pair of well-defined and quasi-reversible redox peaks appeared with the formal potential as -0.219 V (vs. saturated calomel electrode) in pH 7.0 phosphate buffer solution, indicating that the direct electrochemistry of Mb was realized on the modified elecctrode. Mb exhibited a surface-controlled process and the electrochemical parameters were calculated. The Mb electrode showed good electrocatalytic ability to the reduction of trichloroacetic acid within the concentration range from 1.0 to 16.0 mmol/L and the Michaelis-Menten constant was calculated as 7.378 mmol/L. The proposed bioelectrode exhibited good stability and repeatability with the potential application in third-generation biosensor.