DNA purification is a vital step in many molecular tests such as PCR and QPCR. It removes contaminating proteins, salts, and other impurities that can hinder the downstream process. It also ensures the desired DNA is pure and is present so that it can be used for further analysis. The quality of DNA can be determined using spectrophotometry (the ratio of A260 to A280) or gel electrophoresis and other methods.

The first step in the DNA purification process is cell lysis, in which the cellular structure is broken with detergents or reagents like SDS to release DNA. To further purify DNA, reagents designed to are able to denature proteins like sodium dodecylsulfate or Ethylene Diamine Tetraacetic Acid (EDTA) can be added to denature them. The proteins are then removed from the nucleic acid solution by centrifugation and then washing. If there is RNA in the sample, a ribonuclease treatment can be added to further denature RNA. The nucleic acid is diluted with ice-cold ethanol to make it distinct from other contaminants.

Ethanol can be utilized as solvents to eliminate salts and other contaminants from nucleic acids. Researchers can compare results from different experiments by using a standard ethanol concentration, which is a good choice for workflows with high-throughput. Other solvents such a chloroform and phenol can be used, but these are more harmful and could require additional steps to prevent cross-contamination with other cellular debris or proteins. The process of purifying DNA http://www.mpsciences.com/2021/04/23/dna-purification-processes-for-different-applications/ can be simplified by using ethanol with low ionic strength. This has been shown to work as well as conventional organic solvents in making DNA purer. This is particularly relevant when used in conjunction with a spin column extraction kit.