Objective To develop a column chromatographic method for purification of typhoid Vi polysaccharide instead of traditional phenol extraction combined with ethanol fractionation.Methods One batch of crude typhoid Vi polysaccharide was purified by DEAE ion exchange chromatography using 20 mmol / L Tris-Cl as buffer at pH 6.0,7.0 and 8.0 respectively,serving traditional phenol extraction combined with ethanol fractionation as control.The purified Vi polysaccharide was determined for protein,nucleic acid,O-acety...