Assessing the purtiy of DNA Sample

[Gamewizard]

Hi

 

does anyone know how to assess the purity of the DNA sample, the 260/280 ratio for pure DNA is 1.8- 2.0 ?

 

I extracted the DNA and my concentration was ng/ul 45.1 and the optical density was 2.06.

 

please help me solve this

[CharonY]

The 260/280 ratio is based on the absorbance of the sample measured at the indicated wavelength. On OD of 2 is rather odd unless you factored dilutions in. Most photometers are unreliable with values near 1.

[Greippi]

An OD of 2.06 is MAD. I'm pretty sure your spectrophotometer will only be accurate below 1. You can't make sensible calculations with 2.06. Dilute your sample 1 in 10 and read again.

 

EDIT: I'm sorry, CharonY pretty much said this. Also didn't notice how old the thread was.

Edited December 10, 2010 by Greippi