DNA purification is one of the most common and important procedures in molecular biology. Purification of DNA is aimed at separating the desired genetic material (chromosomal material) from other contaminants, such as proteins as well as RNA and cell membrane. This is a crucial procedure in almost every molecular process and must be carried out correctly to ensure high-quality usable DNA.

There are many different methods available for DNA purification, the selection of which is dependent on a number of aspects, including the materials used to start and downstream applications and costs and time limitations. The standard genomic and plasmid purification techniques involve chemical treatment, enzymatic digesting or mechanical disruption of cells and tissues, followed by salting out proteins and then precipitating the DNA using alcohol.

Ethanol precipitation is a cheap easy and quick method of desalting and concentration DNA. DNA molecules form aggregates when they are in the presence of monovalent cations such sodium and then precipitated out of solution by the highest concentrations of ethanol. This method permits the removal of salts, organic compounds and other impurities from a sample. It is often employed in conjunction with other purification techniques.

Another method that is popular for DNA purification is anion exchange chromatography. DNA in solution is linked to positively charged resins by the interaction between the negatively charged DNA phosphate backbone as well as the positively charged surface molecules of the resin. During the binding and washing processes the contaminating molecules are removed from DNA through rigorous wash steps and the purified DNA is eluted in low salt conditions.

https://mpsciences.com/2021/04/08/different-types-of-pcr-reagents/