LIGAND-EXCHANGE CHROMATOGRAPHY OF CARBOHYDRATES AND GLYCOCONJUGATES

The current status of ligand-exchange chromatography (LEG) is reviewed in the light of recent developments, especially regarding mobile phas e conditions and choice of metal ions. Further, parameters governing s electivity are emphasized. The paper is divided into two parts: LEC at acidic/neutral pH and at alkaline pH. The general characteristics of each part are outlined and illustrated by appropriate applications, in cluding bioanalysis of carbohydrates in complex mixtures. In particula r, the exceptionally strong complexation between carbohydrates and cer tain metal ions at alkaline pH appears promising for enrichment and cl ean-up possibilities owing to the high degree of inherent selectivity, Finally, future directions are discussed with regard to the intricate isolation and separation problems associated with glycotechnology. Fu rther advances within this field will depend on the development of ana lytical methodologies for minute amounts (femtomoles) of complex carbo hydrate mixtures present on proteins, receptors and cell surfaces and inside the cells.