Voltammetric investigation on interaction of protein with chromotrope 2R and its analytical application

The electrochemical behaviors of the interaction of chromotrope 2R (CH2R) with human serum albumin (HSA) are investigated on the hanging mercury drop electrode with linear sweep voltammetry. In the acidic buffer solution (pH 2.5) CH2R has a well-defined voltammetric reductive wave at −0.34 V (SCE). On the addition of HSA into the CH2R solution, the reductive peak current of CH2R decreases with little movement of the peak potential. The voltammetric study shows that the electrochemical parameters of interaction solution do not change and a new electrochemically non-active complex is formed via interaction of CH2R with HSA, which cannot be reduced on the Hg electrode and results in the decrease of the free concentration of CH2R. The decrease of reductive peak current is proportional to HSA concentration and further used for protein detection. The binding ratio and the binding constant are further calculated with the experimental voltammetric data.