DNA purification is an essential component of many molecular assays, including PCR or qPCR as well as DNA sequencing. It eliminates proteins that have been contaminated as well as salts and other impurities which hinder the downstream process. It also ensures that the desired DNA is pure and present to be further analysed. The quality of DNA can be determined through spectrophotometry (the ratio of A260 to A280) as well as gel electrophoresis and other methods.

The first step in a DNA purification procedure is cell lysis, in which the cellular structure is disturbed with detergents or reagents like SDS to release DNA. To further purify DNA, protein-denatured reagents like sodium dodecylsulfate and Ethylene diamine tetraacetic acid (EDTA) are added to denature proteins. They are then removed from the nucleic acid solution using centrifugation and wash steps. If RNA is present in the sample then it can be further denatured by adding ribonuclease. The nucleic acids are then concentrated in ice-cold alcohol to separate them from other contaminants.

Ethanol is a common solvent that can be used to eliminate salts and other contaminants click this link now from nucleic acids samples. Researchers can compare results from different experiments by using a standard ethanol concentration, which is a good choice for workflows that require high-throughput. Other solvents, such as chloroform or phenol, could be used, but they are more toxic and require additional steps to prevent cross-contamination. Newer methods can make it easier to complete the process of DNA purification by using ethanol with low-ionic strength, which has been shown to be as efficient as conventional organic solvents in purifying DNA [26]. This is particularly relevant when used in conjunction with a spin column extraction kit.