Voltammetric Study of Adenine Complex with Copper on Mercury Electrode

The determination of adenine (Ade), adenosine (Ado) and hydrolyzed adenosine (h-Ado) in the presence of copper(II) ions is described by cyclic (CV) and elimination voltammetry with linear scan (EVLS) in connection with adsorptive stripping technique. Signals of adenine and copper-adenine complex were measured on a hanging mercury drop electrode (HMDE) in buffered solutions with different pH. The differences in electrochemical behavior of Ad,and Ado were found not only in dependence on the presence of copper ions, scan rate, Ade concentration and pH, but also on the accumulation time and potential where a copper-Ade complex is formed. A deeper evaluation of voltammetric responses was carried out by EVLS. The EVLS function E4 eliminating charging and kinetic current components and conserving the diffusion current component was capable of enhancing the current sensitivity of CV peaks and of detecting electron transfer in adsorbed state. The irreversible electrode process of a totally adsorbed electroactive species is indicated by means of a peak-counterpeak signal. Our results show that EVLS in connection with the adsorptive stripping procedure is not only a useful tool for both qualitative and quantitative microanalysis of Ade but also for revealing certain details in electrode processes.