Qiagen’s QIAquick DNA clean up kits are marketed in three different forms. These are the PCR purification kit, the nucleotide removal kit and the gel extraction kit. The principle behind all three is very similar. I have personally used two of the three: the PCR purification kit and the gel extraction kit. I favor the PCR purification kit simply because it saves excising bands from agarose gels to purify the DNA fragment and yields more DNA than from gel extraction. In some cases the gel extraction kit is more applicable, for example if a PCR reaction generates multiple amplification products or the original source of DNA to be purified is from a different experiment which may contain contaminants that this kit can not effectively remove. In the case that a PCR reaction has resulted in one clear DNA band identified by agarose gel electrophoresis, using the QIAquick PCR purification kit is my favored approach.
I use this kit when I want to either clone or sequence a DNA fragment that I’ve been able to amplify by PCR. This is a fairly common application in the lab for us, so the consistency and robustness of this kit are important to me. The manufacturers state that the kit is able to purify single- or double-stranded DNA fragments ranging from 100 bp to 10 kb in length. Many plasmids and vectors are bigger than this, which is why PCR products from plasmids can also be purified.
components, and contamination risk.