Protocol Online logo
Top : New Forum Archives (2009-): : Molecular Biology

DNA Quantification - Problems with DNA Quantification (May/10/2011 )


I had a question about the quantification of DNA using the Nanodrop,

I amplified my DNA using normal PCR amplification i purified it with a Qiaquick PCR purification kit and then i measured my samples using the nanodrop, i had the following results:

Concentration (ng/ul) = 18,0
260/280 nm = 1,78
260/230 nm = 2,88!! <- This value concerns me

Does anyone of you have an idea what this high value means, i have looked up some forums and they said it was because the concentration of the DNA was too low but i don't think that this is the problem.

Fact about the DNA molecule, the 5' strand of the DNA molecule has a NH2-C6 group attached to it, could it possibly be some kind of absorbance either from the NH2 or the C6 chain?

Can anyone help me?


well the peptide bond does absorb at 230 nm... which is CO-NH so may be even NH2 does.. not sure though!!!!


I think you want to look at the full spectrum to tell what is going on. It's possible that residual PB or QG buffer contributes to these results. Good luck!