Chelex 100 is a
chelating material from
Bio-Rad used to purify other compounds via
ion exchange. It is noteworthy for its ability to bind
transition metal ions.
It is a
styrene-divinylbenzene
co-polymer containing
iminodiacetic acid groups.
A concentrated solution of metals is obtained by eluting the resin with a small volume of 2
M nitric acid, which protonates the iminodiacetate groups.
Chelex
resin is often used for
DNA extraction in preparation for
polymerase chain reaction by binding to cations including Mg
2+, which is an essential cofactor for
DNases. Chelex protects the sample from DNases that might remain active after the boiling and could subsequently degrade the DNA, rendering it unsuitable for PCR. After boiling, the Chelex-DNA preparation is stable and can be stored at 4°C for 3–4 months.
Polar resin beads bind polar cellular components after breaking open cells, while DNA and RNA remain in water solution above the Chelex resin.
However, the heating steps do denature the double helix, and the resulting
single-stranded DNA is less stable in storage.
References
* Daniel Harris. ''Quantitative Chemical Analysis'', seventh edition, 2007. . Page 594.
* {{cite journal , author1=R. N. Ceo , author2=M. R. Kazerouni , author3=K. Rengan , doi = 10.1007/BF02040660 , title = Sorption of silver ions by Chelex 100 chelating resin , year = 1993 , journal = Journal of Radioanalytical and Nuclear Chemistry, Articles , volume = 172 , issue = 1 , pages = 43–48 , s2cid=94639747
External links
Official site
Chelating agents