Concentration of DNA by Ethanol Precipitation Protocol. Adapted fromBruce A. Roe, Department of Chemistry and Biochemistry, The University of Oklahoma, Norman, Oklahoma. Usually 2.5 - 3 volumes of ethanol and/or acetate solution is added to the DNA in a microcentrifuge tube. This is then put into an ice-water bath for at least 10 minutes. The precipitation is performed by incubation at -20C overnight.