I'm trying to extract DNA from the organic phase left over from RNA isolation with RNA bee.
Measuring the yield with the Nanodrop, after adding 8mM NaOH, shows sufficient amount of DNA, but the 260/280 ratio is on average 0.35 in stead of 2.0, indicating polution with proteine or phenol.
I think the problem lies in washing the DNA with 0.1 M Sodium Citrate in 10% EtOH (2.94 g in 100 ml 10% EtOH). After 2 or 3 washes, I could still see traces of phenol. Is this the right concentration or does someone have other ideas on what might cause the low 260/280 outcome?