TYPE-C™ is the unique "Silica-Hydride" that has a double point of attachment to the C18 ligand with direct silicon-carbon bonds with no end-capping. This makes the Cogent Bidentate C18™ phase the most stable C18 on the market. Due to the Hydride surface, these columns do not develop the typical water shell that occurs in other stationary phases. Lack of this hydration shell allows for some very unique features including operation in ANP (Aqueous Normal Phase), NP (Normal Phase) and RP (Reversed Phase) with the ability to change modes without hysteresis. The Cogent, Bidentate C18™ column is very hydrophobic compared to most C18 columns. and is listed separately on this website. Click HERE for ordering information..
Traditional "Type-B", spherical, low-metal content silica with exhaustive end-capping is the most commonly used column for Reversed Phase methods. These include the MOST POPULAR** Cogent RP™ C18, Cogent RP C18 ABX™, Cogent RP C18 PE™ and others, including Similars™ Columns.
Irregular, Type-A silica bonded C18 with and without end-capping for older USP® monographs or in-house methods matching the stationary phases used to develop the monographs.
The Cogent MicroBee C18™ is made to be similar to Microbondapak® C18.