OD C18 Columns

SMT SAM OD C18 columns are usually the first column of choice for reversed-phase chromatographic separation or method development. When compared to other columns such as a C8, C4, CN, phenyl, or an amino bonded phase, C18 is the most hydrophobic. 

 

SMT SAM OD C18 columns are very stable at a wide pH range and high temperatures. Separation of most basic solutes is often possible without trifluoroacetic acid (TFA) or other mobile phase additives. SMT packings enable you to achieve a broader pH range than what is accessible with other commercially available packings. SMT utilizes a novel self-assembled monolayers technology in all its bonding chemistries to achieve maximum coverage. The technique involves pretreatment of the silica substrate including rigorous control of water molecules. A mixture of trifunctional ligands is then allowed to come in contact with the substrate. The result is an unprecedented high-density assembly of molecules on the substrate. The unique aspect of SAM is that only a monolayer of coverage is achieved when the bonding is performed accordingly.  At least one of the  ligands (e.g. C18) is functional for the separation while the other (e.g. C1) is used as a spacer molecule, although, it too can impact certain selectivity needed for some separation. A typical coverage achievable with SAM is 7-8 μmole/m2. This coverage value is equivalent to the maximum achievable coverage on any substrate and it is about 50% higher than that achievable using the most exhaustive conventional bonding and end-capping methods available in the market today.    

 

OD Series: SAM C18 phase with the highest functional ligand coverage confirmed with carbon analysis results of 24% carbon load. In these series, a very high density of the functional ligand, octadecyl (C18) molecule, is achieved through meticulous mixture of the C18 with proprietary spacer molecules to ensure maximum coverage. These phases are very hydrophobic and are designed to tolerate usage in very aggressive pH conditions and high temperatures.