High 260/280 ratio - what does it mean? - (Jan/11/2006 )

You also have to consider the pH of the solution used for elution. For pure RNA 1.8 up to 2.3 indicate pure RNA, but for ph=7.5 .
If you use the H20 RNase free provided with RNeasy kit, the ratio is normally slightly lower as the pH of water is not buffered when provided.

Hi everybody

About this topic, I have measured the same samples in 2 different spectometers. In one of them, 260/280 ratio was 1.8 while in the other it was about 2.1-2.2. So it seems that different spectometers can provide different ratios. The 260 nm value was always the same, so the problem comes with the 280 lecture. I suggest if you have the oportunity to use another UV, try what happens.