Comparison between the behaviour of native and denatured DNA at mercury and gold electrodes by capacity measurements and cyclic voltammetry

The effect of the double-layer structure on the adsorption of DNA has been studied by comparing its behaviour at Hg and Au interfaces. Some features of the adsorbing behaviour are studied by the use of combined cyclic voltammetry and capacity measurement. The results illustrate the common characteristics at both interfaces as regards the lowering of the capacity in the vicinity of the pzc, although the kinetics of the process is different on the two metals. The adsorption behaviour at larger values of the charge cannot be compared directly because on Hg this is masked by a reduction at negative charges which does not occur in the accessible range on Au, while an oxidation occurs at positive charges on Au.