Polysaccharides cellulose derivatives

Among the polysaccharides, cellulose derivatives are often used as good barrier properties against gas as oxygen, with good mechanical properties but often permeable to water. A wide variety of possible coatings offer many possibilities for controlled release (Clark and Shen, 2004). 

Plant stmctural material is the polysaccharide cellulose, which is a linear P (1 — 4) linked polymer. Some stmctural polysaccharides iacorporate nitrogen iato thek molecular stmcture an example is chitin, the material which comprises the hard exoskeletons of kisects and cmstaceans. Chitki is a cellulose derivative whereki the OH at C-2 is replaced by an acetylated amino group (—NHCOCH ). Microbial polysaccharides, of which the capsular or extracellular (exopolysaccharides) are probably the most important class, show more diversity both ki monomer units and the nature of thek linkages. 

In the previously described electrophoretic methods, the capillary was filled with electrolytes only. Another mode of operation in capillary electrophoresis involves filling the capillary with gel or viscous polymer solutions. If desired, a column can be packed with particles and equipped with a frit.68 This mode of analysis has been favorably used for the size determination of biologically important polymers, such as DNA, proteins, and polysaccharides. The most frequently used polymers in capillary gel electrophoresis are cross-linked or linear polyacrylamide,69 cellulose derivatives,70-75 agarose,76 78 and polyethylene glycols. 

Synthetic products, e.g., polyethylene oxides(104), polyacrylates, polyacrylamides, and polyetherglycols were in competition with natural polymers like starch, guar, cellulose derivatives, alignates, carrageenan, and locust bean gum. The basic physical and structural properties of the various polysaccharide thickeners have been compiled and reviewed by numerous authors and editors(105-109). 

Preweighed 1.0 mg samples of each polysaccharide carbamate derivative were submerged in aqueous solutions at three pH values 3.1 7.0 and 11.3. Three milliliter aliquots were withdrawn at periodic intervals and analyzed by ultraviolet spectroscopy. Typical results are shown in Figures 3 and 4 for pendant hydrolysis rates of carbamate derivatives of cellulose and chitin respectively as a function of pH. 

Cellulose, Amylose and Other Polysaccharide Carbamate Derivatives... 

Several common polysaccharides are derived from glucose including cellulose, starch, and glycogen. These polymeric forms of glucose differ in structure. Cellulose, the most abundant polysaccharide, forms the structural material of the cell walls of plants. Cellulose is a polymer... 

In addition to being necessary for all forms of life, biopolymers, especially enzymes (proteins), have found commercial applications in various analytical techniques. See also Automated Instrumentation Clinical Chemistry Automated Instrumentation Hematology and Biosensors. In synthetic processes (see also Enzymes in Organic Synthesis) and in prescribed therapies (See also Enzyme Therapeutic and Vitamin), Other naturally occurring biopolymcrs having significant commercial importance aie the cellulose derivatives, e.g., cotton and wood, which are complex polysaccharides. 

The cellulose derivatives used for chiral TLC are trisphenylcarbamate, 2,3-dichlorophenylcarbamate, 2,4 -dichlorophenylcarbamate, 2,6 -dichlorophenylcar-bamate, 3,4-dichlorophenylcarbamate, 3,5-dichlorophenylcarbamate, 2,3-dimethyl-phenylcarbamate, and 3,5-dimethylphenylcarbamate. Aboul-Enein et al. [178] have reviewed the chiral resolution of racemates on polysaccharide chiral TLC plates. They discussed the role of the substituents of polysaccharide derivatives on chiral resolution. The effects of the substituents of cellulose derivatives and the mechanisms of chiral resolution on these plates are similar to what is found for HPLC CSPs. 

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