DNA purification is an essential element in a variety of molecular tests, including PCR and QPCR. It eliminates proteins that have been contaminated, salts, and other impurities which hinder the downstream process. It also ensures that the desired DNA is clean and in good condition in order to be used for further analysis. The quality of DNA is determined through spectrophotometry (the ratio of A260 to A280) as well as gel electrophoresis and other methods.
The initial step in the DNA purification process is cell lysis, in which the cellular structure is broken by reagents or detergents like SDS to release DNA. To further purify DNA, protein-denatured reagents such as sodium dodecyl sulfate or Ethylene diamine tetraacetic acid (EDTA) are used to denature proteins. They are then removed from the nucleic acid solution by centrifugation and washing steps. If RNA is detected in the sample and is not removed, it can be denatured by adding ribonuclease. The nucleic acid is diluted using ice-cold alcohol to isolate it from other contaminants.
Ethanol is a popular solvent that can be used to eliminate salts and other contaminants from nucleic acids samples. Researchers can compare results from different tests using an ethanol concentration that is standard, which is an excellent choice for high-throughput workflows. Other solvents like chloroform and phenol may be used, but these are more harmful and require additional steps to avoid cross-contamination with other proteins or cellular debris. The process of purifying DNA can be made simpler by using ethanol that has a low ionic strength. It has been proven to be effective as conventional organic solvents in making DNA purer. This is especially the case when paired with a spin column-based extraction kit.
https://mpsciences.com/2021/04/08/different-types-of-pcr-reagents/