Dear all,
I have a DNA sample with 5 ug/ul conc. but it's 260/280 ratio is 1.21 and 260/230 ratio is 1.55 which indicates that DNA is not pure and has some impurities. So, I want to know whether there is any formula which can tell me how much DNA ( out of 5 ug/ ul) I have in my sample after excluding the impurities ( after substracting the absorbance by impurities which absorb at 260 and 230)?
Thanks
Your DNA concentration still same, i.g. 5 ug/ul. However your DNA not pure, not suitable to analysis and not good for analysis. Sometimes, you need to repeat and try again to get best DNA purity that is suitable for analysis.
A260/280 and A260/230 values greater than 1.8 are typically suitable for analysis.
Lower A260/280 values may indicate protein contamination.
Lower A260/230 values indicate contamination with salts or some solvents (e.g. phenol).
You can't use your DNA for analysis. Impurity and contamination can inhibit the activity of enzymes or the your reaction mixture.
Hope it help!
Hi,
if you have 5µAg/µl DNA concentration I would as a first step dilute and remeasure the DNA becuase very high concentrations sometimes affect the measurments. Apart from this I agree with Mabrur you might need to repurify the DNA or do extraction again (or just give it a try depending on the needed DNA amount and the application e.g. if you only need 5 ng gDNA foor a PCR this is a high dilution of potential inhibitors and the reaction will most likley work)
Sven
Hi Lalita, as the two previous answers said your measured conc. is the exact DNA measurement. Depending what your next steps are clean up may not be needed but it would be recommended. I would also advise diluting the sample if its applicable and re-measure the DNA, its a lot in your mixture nd sometimes this can throw the nanodrop etc off. best of luck
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