Chelex 100 resin is a styrene divinylbenzene copolymer containing paired iminodiacetate ions, which act as chelating groups in binding polyvalent metal ions. The carboxylic acid groups of Chelex 100 resin classify it as a weak cation exchange resin, but it differs from other exchangers in this class by featuring uniquely high selectivities for metal ions and much higher bond strengths. The resin can be used to ultrapurify buffers and ionic reagents: it will scavenge metal contaminants without altering the concentration of nonmetal ions.
Chelex 100 chelating ion exchange resin has a stronger selectivity for copper, iron, and other heavy metal ions over monovalent cations such as sodium and potassium. Its selectivity for divalent over monovalent ions is approximately 5,000 to 1, and it has a strong attraction for transition metals, even in highly concentrated salt solutions.
The following forms of Chelex 100 resin are available:
- Analytical grade Chelex 100 resin — exhaustively sized, purified, and converted to make it suitable for accurate, reproducible analytical techniques
- Biotechnology grade Chelex 100 resin — the analytical grade form certified to contain fewer than 100 microorganisms per gram of resin
Larger volumes and special packaging for industrial applications are available upon request.