Nano-diamond modified electrode for the investigation on direct electrochemistry and electrocatalytic behavior of myoglobin

Abstract Carbon ionic liquid electrode (CILE) was used as the basic electrode, which was coated with nano-diamond (ND), myoglobin (Mb) and Nafion in sequence to construct a bioelectrochemical sensor (Nafion/Mb/ND/CILE). ND had the advantages of large specific surface area and useful electrochemical properties. Spectral analysis indicated that Mb was not denatured or inactivated after mixed with ND. Electrochemical behaviors of Mb on the modified electrode were checked by cyclic voltammetry with a pair of symmetric and quasi-reversible redox peaks exhibited, which proved the acceleration effect of ND to electron transfer of Mb. This Mb sensor displayed excellent electrocatalytic properties to the reduction of various substrates such as sodium nitrite, trichloroacetic acid and hydrogen peroxide with the detection range from 0.02 to 6.60 mmol/L, 1.1 to 30.0 mmol/L and 0.3 to 19.0 mmol/L, respectively. Real sample was detected by this sensor with satisfactory result. Therefore, ND showed potential application to construct third-generation electrochemical biosensor.