Questions about 260/230 when reading DNA conc. - (Jun/12/2009 )

I'm a summer student working in a lab and I've been doing a fair amount of DNA extraction using quigen's DNA extraction microkit. I've been using a Nanodrop to do my concentration readings and while my 260/280 ratios are usually above 1.8, my 260/230 ratios are pretty low-- usually below 0.5. What does that say about my DNA? Can it affect doing PCR on those samples? Any advice on how to clean it up?

Thanks!

Low ratios are bad. . . there's contamination by something. What are you extracting your DNA from? Various things can cause your high 230 reading - phenol, humic acids, salts, polysaccharides, residual ethanol. The residual ethanol might be your easiest thing to troubleshoot first. Make sure NO ethanol gets carried over from your wash and that you're doing your extra 1 minute spin. It can affect your PCR but there's only one way to know . . . try it.

bob stole my cookie on Jun 12 2009, 10:29 AM said: