Electrochemical studies of porphyrin interacting with DNA and determination of DNA

A voltammetric study of the interaction of TMAP with DNA on Hg electrode in ammoniacal buffer solution is described. Adding DNA in TMAP solution, the Ip value of all three peaks of TMAP decreases, and Ep of P2 and P3 shifts negatively, which is consistent with the results of decreasing TMAP concentration. In the presence of DNA, no new peaks appear, and the electrochemical parameters (standard rate constant ks, transfer coefficient α, diffusion coefficient D) of TMAP have no significant change. Electrochemically non-active complexes such as DNA-TMAP and DNA-2TMAP are formed when TMAP interacts with DNA. When DNA was added in 2 × 10−6 mol l−1 TMAP solution, the Ip1 of TMAP decreases in proportion to the DNA concentration from 5 × 10−7 to 1 × 10−5 mol l−1. The results of samples determination by electrochemical method are consistent with those by UV-spectroscopy.