Analysis of sugars using paper chromatography (Horizontal migration)

Summary

Employing filter-paper chromatography a convenient method (Horizontal Migration Method) has been developed for the identification of reducing sugars, when present either alone or in mixtures. Since only small amounts are required for the identification, the method may be useful both to the regular student and the research worker. Under the conditions of the experiment the components of mixtures separate in 1/2 to 1 1/2 hours into circular zones, which can be easily detected by spraying with a suitable reagent like aniline hydrogen phthalate. Each sugar has its own characteristic circular R_F value (the ratio between the distances through which the sugar moves on the one hand and the solvent front on the other) with a particular solvent, and its determination enables the identification of the sugar. Since some of the sugars have the same or very close R_F values with a particular solvent, it is desirable to run the chromatogram with at least 2 different solvents to confirm the identification. In the case of mixtures it may be necessary to determine the R_F values with 3 or more different solvents in order to definitely identify the individual components. Some of the advantages of the method are the speed and ease of manipulation, simplicity and compactness of the apparatus, and accuracy and reproducibility of the results.