The absorbance (OD) of a given DNA depends on its composition. Each nucleotide displays a particular molar extinction coefficient ( ε = epsilon) and significant differences occur between nucleotides. Adenosine-5-phosphate has an ε value (expressed as L. mol-1 cm-1) of around 15,000, guanosine and cytidine around 9,000, and thymidine arround 10,000.

I hope that this can help

Dear Prof. Yannis,

Thanks for your response. Based on your given information and Beer-Lambert law, is it right that I say:

When a ssDNA has more adenosine in its structure then absorbance is more in compare with the other ssDNA with less adenosine in the same number of nucleotides?

Thanks in advance for your help and sharing your knowledge.

Yes, this is a good reasoning

Thank you for your guidance dear. Prof. Yannis.

Using its molar extinction coefficient you may apply to check its purity with additional CD spectrum.

Thanks Dear Prof. Daryono for your answer and concern.