Effects of ex situ chronopotentiometric analysis on stability of bovine serum albumin on mercury electrodes

Abstract Constant current chronopotentiometric stripping (CPS) allows analysis of proteins based on measured peak H resulting from catalytic hydrogen evolution reaction. The technique is label-free and sensitive to the structure and stability of the protein adsorbed at the mercury electrode. Comparison of proteins must be carried out under the same conditions, including ionic strength, temperature, pH, and accumulation potential and time, as all of these factors can affect the protein stability and structure on the electrode surface. Here we show that for bovine serum albumin, uncontrolled disconnection of the cell after accumulation, as is necessary for ex situ CPS measurements can cause an increased susceptibility to electric field-induced denaturation during the subsequent CPS measurement. This destabilization is attributed to oxidation of the Hg electrode during disconnection. For this reason, care much be taken when ex situ CPS measurement of protein is performed.