Electrochemical studies of the interaction of Basic Brown G with DNA and determination of DNA.

A new method of electrochemical probe has been proposed for the determination of Herring Sperm DNA (DNA) based on its interaction with Basic Brown G (BBG). The electrochemical behavior of interaction of BBG with DNA was investigated on Hg electrode. In 0.1molL(-1) NH(3)-NH(4)Cl buffer solution (pH 8.0), BBG can be reduced on Hg electrode with a well-defined voltammetric peak at -0.67V (versus SCE). In the presence of DNA, the reduction peak current of BBG decreases and the peak potential shifts to a more positive potential without the appearance of new peak. The study shows that a new BBG-DNA complex is formed by linear sweep voltammetry (LSV) and spectrophotometry. The decrease of the second order derivative of reductive peak current (Delta i(")(p)) of BBG is proportional to the concentration of DNA in the range of 0.10-36microg mL(-1). Limit of detection of DNA is 0.04microg mL(-1). DNA of Hepatitis B Virus in serum samples was determined satisfactorily. Additionally, the binding mechanism was preliminarily discussed. The mode of interaction between BBG and DNA was found to be intercalation binding.