Electrolyte effects on enzyme electrochemistry

The electrolytes used in enzymatic biosensors or biofuel cells have always been considered to be inert. However, recent studies have demonstrated that this assumption is not correct and that the nature of the electrolyte needs to be considered. Ion-specific interactions can occur with the faradaic response observed in both direct and mediated electron transfer being modulated by the nature of the salt used in solution. Specific ion effects arise from the Hofmeister series, which is well established in studies of protein systems but not in electrochemical studies of redox enzymes. Recent experimental and theoretical work on explaining the Hofmeister effect is described.