Keywords: electrode modifications, surfactant/myoglobin films, electrocatalysis, bisulfite reduction
Summary:Abstract In this report, the surfactant, didodecyldimethyl ammonium bromide (DDAB), is used to immobilize myoglobin (Mb) onto a glassy carbon (GC) electrode. The Mb/DDAB film on GCE showed a good charge transport, allowing Mb to be used as a redox catalyst for reactions requiring multi-electron transfer of bisulfite reduction. The modified electrode showed electro catalytic activity towards the multi-electron reduction of bisulfite. Various electrochemical methods including cyclic voltammetry, coulometry and chronoamperometry have proved the modified electrode to be an effective electro catalyst for the multi-electron reduction of bisulfite. Based on cyclic voltammetric and chronoamperometric studies, the film has a heterogeneous electron transfer rate constant of 30.0 ± 0.2 s-1 with a catalytic rate constant for bisulfite reduction in the range of 103 M-1 s-1 in pH 7.3 Tris buffer solution. The variation in the catalytic rate constant values with pH confirmed that the bisulfite is the reactive oxysulfur species. Electrocatalytic reaction of bisulfite reduction at Mb/DDAB films followed EC’ catalytic mechanism.