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 I-p value of all three peaks of TMAP decreases, and E-p, of P-2 and P-3 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 k(s), transfer coefficient alpha, 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 2x10(-6) mol l(-1) TMAP solution, the I-p1 of TMAP decreases in proportion to the DNA concentration from 5 x 10(-7) to 1 x 10(-5) mol l(-1). The results of samples determination by electrochemical method are consistent with those by UV-spectroscopy.