Electrochemical studies of the interaction of 9,10-anthraquinone with DNA 2. Chemically modified electrode

The electrochemical behavior of DNA at a glassy carbon electrode modified by 9,10-anthraquinone was studied. The cyclic voltammogram of 9,10-anthraquinone CME in 0.10 mol/liter B-R buffer of pH 5.7 exhibits a redox wave at -0.48 V (vs SCE). On the addition of DNA in solution, both reduction and oxidation currents decrease, but with no change in the peak potentials. It is found that the decrease of reduction current is proportional to the concentration of DNA over the range from 5.0 x 10(-7) to 8.0 x 10(-6) mol/liter with a correlation coefficient of 0.9963. But in the B-R buffer at pH 8.9, the redox wave of anthraquinone CME shifts to -0.68 V, and the voltammogram obtained upon addition of DNA shows an increase in both reduction and oxidation currents. The CME modified by anthraquinone shows significant two-way electrocatalytic activity on DNA. (C) 1998 Academic Press.Chemistry, AnalyticalSCI(E)12ARTICLE2307-3145