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Chemically bonded aminopropyl silicas are the most widely used for the hydrophilic interaction chromatography of carbohydrates. The mobile phases consisting of acetonitrile- water mixture are usually employed. All of the commercial columns used for carbohydrate chromatography are packed with porous sorbents. In a column packed with porous sorbent, mass transfer effects due to pore diffusion of solutes into and out of the sorbent may result in a longer elution time. However, when non -porous silica sorbents are employed as packing materials. The solutes can be rapidly separated on the column.
In this research, the non-porous silica having an average diameter of 3.04 μm was prepared . The non-porous silica was silanlized with α-aminopropyltriethoxy silane to introduce terminal amino groups with a densityof 1.98 μmole/m2 on the surface. It is believed that the modified silicacovered a monolayer of silane on its surface. The resultant aminopropyl- silicasthen were packed into two columns (5 cm×0.46 cm I.D. and 10 cm×0.46 cm I.D.). The mixture of glucose and lactose could be separated in 3 min in the 5-cm long column at a flow rate of 0.5 ml/min. The maximum loading capacity of this column was determined to be 5 μg. A sample with a glucose concentration down to 0.1 mg/l could be quantitatively analyzed. The results indicated that the column was suitable for analysis of low sugar concentrations. The lowest value of plate height could be reached by reducing the flow-rate to 0.35 ml/min .The 10-cm long column was effective for the separation of fructo-oligosaccharides produced from sucrose solution catalyzed by β-fructofuranosidase. The separation on the 10-cm long column was accomplished in 8 min at a flow-rate of 0.5ml/min . Whereas it took 24 min to conclude the separation of fructo -oligosaccharides products on the Supelcosil LC-NH2 column (25 cm×0.46 cm I.D.) with a flow-rate of 1ml/min. However, due to the low bindingcapacity of the prepared column, fructose could not be effectively separatedfrom sucrose.
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