High OD ratio from DNA Maxi Prep - (Jan/09/2008 )
After a maxi prep, I checked the OD.
3 pellets were resuspended in 300uL of EB each and the other 3 were resuspended in 300uL of sterile H2O. So each totals to ~900uL.
I used 5uL DNA in 95uL H2O.
EB= 260 reading of .781 and 280 reading of .305
H2O= 260 reading of .905 and 280 reading of .353
What would cause this high ratio? And is this good or bad?
Thanks.
-JatGenetics-
you still have some contaminations.
it xould be interesting to have the OD230 value too.
At first, re pellet your DNA, do extensive 70%ethanolwash, dry efficiently the pellet (sensitive step) resuspend and recheck respective od.
if contamination still occurs, trat with proteinase K and RNAse A, and do a phenol chloroform extraction.
-fred_33-