SMT SAM-C18 or [OD] column is 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-C18 column is 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.
Important Information about of SMT SAM -Columns
It is very important to point out that SMT-C18 columns, as well as all the other columns introduced in this catalog, are unique in their applications; these are not just a “me too products” and while in most cases, the columns may show relatively similar selectivities when compared with other commercially available C18 columns in the market, subtle differences in separation of most complex molecules are often possible. All SMT columns contain mixed ligands that are necessary for the extremely high stability and surface coverage. Furthermore, all columns are made with SAM technology and are designed to be truly base-deactivated. This fact is demonstrated by the chromatograms of an organic cation, Ru(bpy)32+ on SMT SAM-C18 and some competitors’ columns.
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