Direct electrocatalytic oxidation of adenine and guanine on carbon ionic liquid electrode and the simultaneous determination

A carbon ionic liquid electrode (CILE) was fabricated by using an ionic liquid of N-butylpyridinium hexafluorophosphate (BPPF6) as binder and further used for the simultaneous detection of adenine and guanine. The direct electrooxidation behaviors of adenine and guanine were carefully investigated on the CILE. The results indicated that both adenine and guanine showed the increase of the oxidation peak currents with the negative shift of the oxidation peak potentials in contrast to that on the traditional carbon paste electrode (CPE). The electrochemical parameters of adenine and guanine on the CILE were calculated and a new electroanalytical method was established for the detection of adenine and guanine, respectively. The CILE exhibited good behaviors in the simultaneous detection of adenine and guanine with the peak separation as 0.304 V. The measurements of thermally denatured single-stranded DNA (ssDNA) were further carried out and the value of (G + C)/(A + T) of ssDNA was calculated as 0.81.