The Basics of DNA Purification

DNA purification is a vital component of many molecular assays that include PCR, qPCR, and DNA sequencing. It removes contaminating proteins salts, proteins, as well as other impurities which hinder the downstream process. It also ensures that the desired DNA is in good condition and pure in order to be used for further analysis. The quality of DNA can be analyzed using spectrophotometry, gel electrophoresis and various other methods.

The first step of the process of purifying DNA is cell lysis, in which the cell structure is destroyed with detergents or reagents such as SDS to release DNA. To further purify DNA, protein-denatured reagents such as sodium dodecylsulfate and Ethylene diamine tetraacetic acid (EDTA) are added to denature proteins, and they are removed from the nucleic acid solution with centrifugation and wash steps. If there is RNA present in the sample then a ribonuclease treatment may be added to further denature RNA. In the end, the nucleic acids is diluted with ice-cold ethanol to isolate it from other contaminants.

Ethanol can be used as a solvent to remove salts or other contaminants from nucleic acid. Researchers can evaluate the results of different experiments by using a standard ethanol concentration, which is an excellent choice for high-throughput workflows. Other solvents, like chloroform or phenol, can be used, however, they are more hazardous and require additional steps to avoid cross-contamination. The purification of DNA can be made simpler by using ethanol that has a low ionic strength. It has been proven to work just as traditional organic solvents at cleaning DNA. This is particularly relevant when used in conjunction with a spin column-based extraction kit.