Promotion of the redox reaction at horseradish peroxidase modified electrode combined with ionic liquids under irreversible electrochemical conditions

Abstract

We have examined the direct electron transfer of horseradish peroxidase (HRP) in a HRP-modified electrode combined with ionic liquids by adding N-(2-methoxythethyl)-N-methylpyrrolidinium bis(trifluoromethane sulfonyl)imide (MEMPTFSI) to HRP/carbon paste (CP)/Ketjenblack EC600JC (EC) system under irreversible electrochemical conditions. The electroactive surface area of HRP/CP/EC/MEMPTFSI-modified electrode excluding the influence of the CP, EC, and MEMPTFSI materials on the electrode in the presence of 1 mM potassium ferricyanide(III) (K3Fe(CN)6) and potassium hexacyanoferrate(II) (K4Fe(CN)6) ([Fe(CN)6]3−/[Fe(CN)6]4−) as mediators was estimated to be 0.16 cm2. The average rate constant (ks) correlated with the redox current of [Fe(CN)6]3−/[Fe(CN)6]4− only contributing by HRP component within the HRP/CP/EC/MEMPTFSI-modified electrode was calculated to be 0.25 s−1.

Keywords

• Irreversible electrochemical system
• Electroactive surface area
• Rate constant
• Horseradish peroxidase (HRP)-modified electrode
• Enzyme/ionic liquid-modified electrode