Study of the interaction of CTZAMB–Cu(II) with DNA and the determination of DNA

In this paper, the electrochemical behavior of the CTZAMB–Cu(II) complex with DNA has been investigated in potassium hydrogen–phthalate buffer solution (pH 2.5). In the absence of DNA, there was a sharp reduction peak in the single sweep polarogram due to the presence of CTZAMB–Cu(II), while in the presence of DNA this peak decreased in a quantitative fashion. This decrease in peak current is due to the formation of the CTZAMB–Cu(II)–DNA complex. Under the optimum conditions, the decrease of peak current is linear with DNA concentration in the range from 3.0 × 10−7 to 7.0 × 10−6 g ml−1, and the detection limit is 1.0 × 10−7 g ml−1. This new method exhibits a good recovery and sensitivity, which could be applied to the determination of DNA in real samples. The mechanism of the interaction of DNA and CTZAMB–Cu(II) is also discussed.