TLC separation of carbohydrates on silica gel modified with copper (II) salts

Impregnation of silica gel was conducted by immersion method with the help of copper (II) sulfate and ammonia complex: Cu(NH3)4(2+). The adsorbents thus obtained were used for the analysis of carbohydrates of mono-di-oligosaccharides. The influence of the pH of the impregnating solution (pH = 5 and pH = 8) on the retention of the analysed compounds was examined. The results were interpreted in view of the process of metal ions complexation by sugar molecules in water. The effects of organic modifiers: propanol-2, methyl-ethyl ketone, acetonitrile, acetone added to the water phase on the retention and selectivity of the sugars determination on the modified stationary phase were studied.