A Carbon Molecular Sieve (CMS) is the porous carbon skeletal framework remaining after the pyrolysis of a polymeric precursor. Due to their high porosity, these materials are primarily used for collecting very small molecular-sized compounds (C2-C5). The size and shape of an analyte molecule and the size and shape of the pores in the CMS particle determine how well the analyte is adsorbed and desorbed. These materials are hydrophobic and can be used to ensure accurate sampling in high humidity environments.
All our CMS materials are prepared from the highest purity polymers, resulting in highly pure products that ensure effective release/desorption of analytes of interest. Trapped C2-C5 compounds can be desorbed either by solvent desorption or thermal desorption techniques, at virtually 100% desorption efficiency. Because these adsorbents offer excellent thermal stability, they exhibit negligible bleed.
As a general rule, CMS materials have a greater relative adsorptive strength compared to Graphitized Carbon Black (GCB) materials. Therefore, analytes with a molecular size >C5 may be strongly retained, and may not release/desorb during the chemical or thermal desorption process. To prevent this, it is recommended to use a weaker adsorbent bed upstream when used in air monitoring tubes, and to use multi-column switching when used in GC columns.
Two CMS product lines are offered. The primary difference is the pore structure.
Carboxen Adsorbents – have through-pore structures, resulting in efficient adsorption/desorption characteristics.
Carbosieve Adsorbents – have closed-pore structures, resulting in strong adsorption characteristics.
