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Carbohydrate Analysis
CARBOSep Columns
Transgenomic manufactures a line of polymeric columns for carbohydrate analysis called CARBOSep columns. CARBOSep columns employ a technique called ligand-exchange chromatography for the separation of monosaccharides, disaccharides and oligosaccharides up to 11 glucose units long.
The principle behind ligand exchange is that each of the hydroxyls on a sugar molecule carry a very slight negative charge. The hydroxyl group on the anomeric carbon can be deprotonated and have a strong negative charge. It is the interaction between these negative charges on the sugar molecule and the positive charge contributed by the metal ion secured to the resin surface that causes the sugars to be retained and thus separated.
Ligand exchange resins are highly sulfonated cation exchange resins that have group 1, 2 or transition series metals loaded on. The sulfonic acid groups on the resin tightly hold the metal ions via an ionic attraction so that it is not released during analysis or through the life of the column. It is this metal ion that provides the positive charge that interacts with the negative charge on the sugar.
During analysis, the carbohydrates are introduced onto the column. The sugars are attracted to the metals via an ionic interaction thus they become weakly bound to the metal ion on the resin. Water will also have a weak ionic interaction with the metals on the column, so the water will exchange with the sugars on the metal sites. This ionic adsorption and desorption occurs for the sugars through the column. Since the ionic charge is different for every sugar, separation of the sugars occurs.
Selectivity is easily controlled by resin type, metal selected, and other factors such as temperature and mobile phase. CARBOSep columns are provided in a large variety of resin types and metals to provide selectivities that meet your separation needs.
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