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question on ethanol precipitation - (Oct/21/2008 )

My lab typically uses isopropanol instead of ethanol for RNA precipitation (samples are paraffin blocks) . Unfortunately I mixed the reagents up by mistake and added 75% ethanol to the mix instead. I'd like to ask if:

1) letting the current mixture of 75% ethanol and sample sit in -20'C for long enough will allow the RNA to precipitate in the end? (since this batch of samples can really,really wait)

2) Adding the original volume of isopropanol back into the mixture will precipitate the RNA?

Thank you very much in advance!


RNA can be precipitated with either 75% ethanol or 50% isopropanol. Just add some 100% ethanol to your sample, adjust to 75% final, and spin, you are done.