Separation and Identification of Methylated Sugars on the Paper Chromatogram

THE identification of the products of hydrolysis of a methylated polysaccharide composed of many different sugar residues is a tedious and difficult task, especially when the polysaccharide is available only in small quantities. We have found., however, that many of the methylated sugars can be readily separated and identified on the paper chromatogram, using the same apparatus and solvents as described for the separation of the simple sugars^1,2. The chromatogram is allowed to run until the solvent has advanced about 40 cm. from the starting line. The paper is then dried and sprayed with ammoniacal silver nitrate, and on warming, the positions of the sugars are indicated by brown spots (except in the case of tetramethylfructopyranose, which reduces ammoniacal silver nitrate only very slightly). As a standard, we use tetramethyl D-glucose, which moves rapidly on the chromatogram. The distance the sugar travels is measured from the starting line to the centre, not the edge, of the sugar spot, since the size of the spot and its leading edge vary with the concentration of sugar solution used. The figure R_G given in the accompanying table refers to the ratio between the distance the sugar travels and the distance through which the tetramethyl D-glucose has moved. (We use this in preference to the R_F value, which tends to vary with the distance the sugar has advanced from the starting line.)