Simple sugars, oligosaccharides, polysaccharides, and their derivatives, including the methyl ethers with free or potentially free reducing groups, give an orangeyellow color when treated with phenol and concentrated sulfuric acid. The reaction is sensitive and the color is stable. By use of this phenol-sulfuric acid reaction, a method has been developed to determine submicro amounts of sugars and related substances. In conjunction with paper partition chromatography the method is useful for the determination of the composition of polysaccharides and their methyl derivatives.C"1 OLORIMETRIC tests for reducing sugars and polysaccha-J rides have been known for a considerable time. The reagents such as 1-naphthol (S3) for carbohydrates in general; benzidine for pentoses and uronic acids (37, 49, 50); naphthoresorcinol for uronic acids (51); and resorcinol ( 43), naphthoresorcinol (39), and resorcinol disulfonic acid (31) for ketoses are well-known examples of colorimetric tests that may be carried out in acid solution. Such tests as these and modifications of them using aromatic amines and phenols (4, 33, 38) have recently gained added importance since the extensive development of partition chromatography for the separation and characterization of minute amounts of sugars and their derivatives (1, 4,

VOLUMETRIC procedures have been used for the quantitative detennination of sugars after separation by partition chromatography 1 • 2 • It has been our experience that these methods not only require considerable skill, but also they are lengthy and sensitive to slight variation of the conditions. We have therefore attempted to develop a simple quantitative colorimetric procedure. , Preliminary experiments showed that the anthrone 3 and the 0(-naphthol sulphonate• reagents give good .results with pure sggar solutions, but the presence of only traces of solvents such as butanol, phenol and propionic acid used in the chromatographic separation of the sugars rendered them useless.It was then discovered that phenol itself in the presence of sulphuric acid provides a simple rapid method for the quantitative colorimetric determination of ketoses and aldoses and their methyl derivatives on a sub-micro scale. The method, applicable to all carbohydrates with either a free or potential reducing group, is particularly useful for determining sugars which have been separated by partition chromatography using phenol-water as the solvent. The orange-yellow colour, produced by adding sulphuric acid (5 ml.) to the sugar solution (2 ml.) containing phenol, is permanent; its optical density (measured at 490 mµ for hexoses and hexuronic acids and their derivatives and at 475 mµ for pentoses and their derivatives) when referred to a standard curve gives the concentration of the sugar.This phenol-sulphuric acid reagent, which has enabled us to determine the composition of polysaccharides and their methyl derivatives on as little as 1 mgm. of material, thus offers an additional method for end-group analysis of polysaccharides 5 • The reaction is not limited to phenol, for certain amines such as N(l-naphthyl) ethylene diamine can replace phenol in the above reaction.In conjunction with the above colorimetric method, it has been found convenient to extract the sugars from the strips of paper cut from the chromatogram by simply immersing them in water.Since the extraction is carried out at room temperature, there is no danger of decomposing the sugars•. Substances in filter paper which interfere with the sugar analysis can be largely removed by three or four 'chromatographic' washings with water; washing with. dilute sodium hydroxide does not seem to improve the paper.Further details of this work.. and its application to the detennination of the structure of various polysaccharides will appear elsewhere.

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Cellulose is a polymeric carbohydrate material and is the basic structural component of the cell walls of trees and other higher plants. It is the world's most abundant organic compound and serves as a chemical feedstock for several commercially important polymer industries. One of the more important of these industries is based on esterification of cellulose with a short-chain aliphatic acid; namely, acetic, propionic, or rc-butyric. The resulting thermoplastic cellulose esters are characterized by exceptional clarity and good mechanical performance. They are found in a myriad of specialty consumer products, some of which are photographic films, fibers, cigarette filters, membranes, and molded articles. Historically, cellulose esters are the oldest manmade thermoplastics, going back to the 1920's. Being plantderived, cellulose is a renewable resource. Cellulose StructureCellulose is a linear polymer of /3-D-glucopyranose units linked through ,d-(l-4)-glycosidic bonds (Fig. 1). From the figure, one can see that there are three hydroxyl groups

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