DNA immobilized on the gold electrode surface could be easily quantified. Kindly refer this article for further clarification.

Article Electrochemical Quantitation of DNA Immobilized on Gold

Shiv Kumar, i had already gone through with this article, which says to use a cationic redox marker, since the phosphate group of DNA is Negatively charged. The cations binds to anion. But how would you quantify the number of cations that has been bound to DNA.

Hi Manohar,

First of all, I think you are starting from a DNA solution with known concentration. You can try to quantify by the intensity of the oxidation peaks of the nitrogenous bases, but a calibration curve is needed.

Alternatively, you can use the more classical quantification by spectrophotometry (absorbance at 260 nm) and evaluating the difference of the amount of DNA in the sample before and after immobilization on the electrode.

I hope I was helpfull.