DNA purification is an essential process in a variety of molecular assays that include PCR or qPCR, as well as DNA sequencing. It eliminates contaminants like proteins, salts and other impurities that could interfere with downstream processes. It also ensures the desired DNA is completely clean and present so that it can be used in future analyses. The quality of DNA can be evaluated using spectrophotometry, gel electrophoresis and other methods.
In the initial step of a DNA purification process the cellular structure is going to be disrupted by detergents or reagents such as SDS in order to release DNA. To further remove DNA, reagents that alter proteins, such as sodium dodecyl sulfate and Ethylene Diamine Tetraacetic Acid (EDTA) can be added to denature them. The proteins are then removed from the nucleic acids solution by centrifugation and washing. If there is RNA in the sample, a ribonuclease treatment can be added to further denature RNA. In the end, the nucleic acids is reacted with ethanol that has been cooled to isolate it from other contaminants.
Ethanol can be utilized as a solvent to remove salts and other contaminants from nucleic acid. Using a standardized concentration of ethanol permits researchers to examine the results of various experiments, making it a good option for high-throughput workflows. Other solvents, like chloroform or phenol, could be utilized, however they are more corrosive and require additional steps to avoid cross-contamination. Newer techniques can simplify the process of DNA purification by using low-ionic-strength ethanol, which has been proven to be just as effective as the conventional organic solvents when purifying DNA [26]. This is especially relevant when used in conjunction with a spin column extraction kit.
