EFFECT OF ELECTROCHEMICAL PRETREATMENT ON PROTEIN ADSORPTION AT GLASSY-CARBON ELECTRODES

Three types of electrochemical pretreatments (ECPs) were assessed as a means of reducing albumin adsorption at glassy carbon electrodes. The cyclic voltammetric and differential pulse responses of the probe analyte, ferrocenemonocarboxylic acid (FCA), in the absence and presence of 4 g L-1 bovine serum albumin (BSA) were used to monitor protein adsorption at pretreated electrodes. Severe dc pretreatment in acid increased BSA adsorption (compared to that at a polished electrode), whereas square-wave pretreatment in aqueous NaCl and dc pretreatment in base both reduced the amount of BSA adsorption. The effects of the latter two ECPs on the response of acetaminophen in the presence of BSA were examined. The loss of sensitivity in the presence of BSA was reduced at electrodes which were pretreated. However, our results suggest that ECP which leads to very strong accumulation of analyte may have a deleterious effect on electrode performance in the presence of protein.