Polysaccharide derivatives applications

The type of CSPs used have to fulfil the same requirements (resistance, loadabil-ity) as do classical chiral HPLC separations at preparative level [99], although different particle size silica supports are sometimes needed [10]. Again, to date the polysaccharide-derived CSPs have been the most studied in SMB systems, and a large number of racemic compounds have been successfully resolved in this way [95-98, 100-108]. Nevertheless, some applications can also be found with CSPs derived from polyacrylamides [11], Pirkle-type chiral selectors [10] and cyclodextrin derivatives [109]. A system to evaporate the collected fractions and to recover and recycle solvent is sometimes coupled to the SMB. In this context the application of the technique to gas can be advantageous in some cases because this part of the process can be omitted [109]. 

More recent developments in the field of the Pirkle-type CSPs are the mixed r-donor/ r-acceptor phases such as the Whelk-Of and the Whelk-02 phases.The Whelk-Of is useful for the separation of underiva-tized enantiomers from a number of families, including amides, epoxides, esters, ureas, carbamates, ethers, aziridines, phosphonates, aldehydes, ketones, carboxylic acids, alcohols and non-steroidal anti-inflammatory drugs.It has been used for the separation of warfarin, aryl-amides,aryl-epoxides and aryl-sulphoxides. The phase has broader applicability than the original Pirkle phases. The broad versatility observed on this phase compares with the polysaccharide-derived CSPs... 

Ion-exchange Celluloses and Sephadex. A different type of ion-exchange column that finds extensive application in biochemistry for the purification of proteins, nucleic acids and acidic polysaccharides derives from cellulose by incorporating acidic and basic groups to give ion-exchangers of controlled add and basic strengths. Commercially available cellulose-type resins are listed in Tables 13 and 14. AG 501 x 8 (Bio-Rad) is a... 

Introduction of an arylamino group into a polysaccharide provides diazotizable products of great utility for enzyme insolubilization, on account of the ease with which diazo groups react with a variety of amino acid side-chains, particularly phenolic ones. Many enzyme derivatives have, therefore, been prepared by use of 0-(4-aminobenzyl) cellulose (38), 0-(3-aminobenzyl)oxymethylcelluIose, and cellulose p-aminoben-zoate. However, although these polysaccharide derivatives could be expected to be widely applicable, the lower enzymic activities often ob-... 

Next, with another of his students, he turned to editing the book Industrial Gums. Now in its third edition, Industrial Gums is a praetieal book that deseribes the chemistry, properties, and applications of water-soluble or water-dispersible polysaccharides and polysaccharide derivatives with commereial value or potential. In the introductory chapter of this book, Professor Whistler presented important concepts about the relationships of structure to properties of polysaeeharides, an area he championed after it had been introduced by D. A. Rees. 

Although there are several types of ionically erosslinked hydrogels, only alginate, a polysaccharide derived from seaweed, is discussed here, because it is the only material widely used for biomedical applications. Alginate is a... 

Natural polymers have also been used as thermo-sensitive hydrogels, either on their own or in combination with other synthetic polymers. Popular natural polymers include chitosan, cellulose derivatives, dextran, xyloglucan and gelatin (Klouda and Mikos 2008). Chitosan is a polysaccharide derived from the shells of crustaceans and is produced by deacetylation of chitin, basically through the removal of the acetyl group using a concentrated NaOH solution (Fig. 11.5). The main advantage of chitosan for medical and pharmaceutical applications is its biocompatibility and inertness when in contact with human cells (Kumar et al. 

The glycopolymers consist of a large family of polysaccharides derived from animals, plants, and microorganisms (Table 4). Due to the diversity of their chemical stmctures as wdl as physical and biological properties, glycopolymers have found a variety of applications in biomedidne, pharmaceutical research, and other industrial domains. 

Applications for separation membranes are many and diverse separation membranes must also function in a variety of conditions. For example, when hydrophilic or hydrophobic membrane materials are desired, they can be easily synthesized because chitin and chitosan have many reactive functional groups, such as hydroxyl and amino groups. These reactive groups are useful for the introduction of functional groups and cross-linkers, and consequently function to strengthen and improve separation membranes. Since chitin and chitosan are polysaccharides derived from... 

Environmental requirements are assuming great importance, since there is an increased interest in the industrial use of renewable resources such as starch and chitin. Considerable efforts are now being made in the research and development of polysaccharide derivatives as the basic materials for new applications. In particular, the increasing cost of conventional adsorbents undoubtedly makes chitin and chitosan-based materials one of the most attractive biosorbent for wastewater treatment. Chitin and chitosan biopolymers have demonstrated outstanding removal capabilities for certain pollutants such as dyes and metal ions as compared to other low-cost sorbents and commercial-activated carbons. Biopolymer adsorbents are efficient and can be used for the decontamination of effluents (removal of pollutants) and for separation processes (recovery of valuable metals). 

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