Preparative chromatography cellulose

Analytical methods can be transferred easily to the preparative scale in polysaccharide-based CSPs, and these compounds have been used in preparative chromatography. Cellulose triacetate, which has good loading capacity, has been used for preparative separation at the industrial scale [70,85]. Moreover, the low cost of cellulose triacetate synthesis makes CTA ideal for preparative chromatography. 

Preparation of Cellulose-Polystyrene Graft Copolymers. The polystyr-yl mono- and di-carbanions were prepared in THF at -78 °C by using n-butyl lithium and sodium naphthalene as the initiators, respectively. The carban-ions were reacted with dry carbon dioxide. The products were precipitated in methanol, filtered, washed with water and methanol, and dried. Size exclusion chromatography (SEC) established that the molecular weight of the polystyryl monocarboxylate was 6,200 and that of the polystyryl di-carboxylate 10,2000. The mono- and di-carboxylates were reacted with mesylated cellulose acetate in dimethylformamide at 75 °C for 20 h to give the cellulose-polystyrene graft copolymer (GP 1) and crosslinked cellulose-polystyrene graft copolymer (GP 2), respectively. 

Fig. 9. Preparative chromatography of bovine ehymotrypsinogen B (105). CM-cellulose column (3.0 X 9.0 cm) equilibrated with 0.05 M citrate, pH 4.2. Arrow indicates change to 0.05 M citrate, pH 4.6. Solid line, potential activity. Dotted line, proteins. The values along the peaks indicate the specific activity of some fractions. I. Chromatography of the precipitate obtained in 0.4 saturated ammonium sulfate (specific activity, 0.9). II. Second chromatography of the fractions having the lowest activity in diagram I. Ordinates, activity or proteins found in each fraction (1 ml) and expressed in per cent of the total activity and total proteins introduced into the column. Abscissas, volume of eluate in milliliters.

The scheme summarises all modern analytical and preparative chromatography protocols, such as high-performance liquid chromatography (HPLC) and gas-liquid chromatography (GLC), with all their conceivable variations. Reverse-phase HPLC or GLC , in which a non-polar liquid is adsorbed onto the solid - the stationary phase - is more appropriate for the analysis of mixtures of derivatives of amino acids and peptides. Cellulose in the above scheme would be replaced by a less-polar medium, such as acetylated cellulose, silanised silica gel, etc. in standard reversed-phase HPLC. 

Although the principal oligosaccharide of milk is lactose, this disacchaiide is accompanied by smaller amounts of other oligosaccharides, which can be separated from lactose by adsorption on activated carbon and elution with dilute acetic acid. The amounts vary somewhat with the mammalian species. In human milk, the concentration, exclusive of lactose, is about 3 g per liter. Preparative chromatography on carbon-Celite and cellulose columns has led to the isolation of live oligosaccharides in pure form (see Table X). 

Diaziridines also show slow nitrogen inversion, and carbon-substituted compounds can be resolved into enantiomers, which typically racemize slowly at room temperature (when Af-substituted with alkyl and/or hydrogen). For example, l-methyl-3-benzyl-3-methyl-diaziridine in tetrachloroethylene showed a half-life at 70 °C of 431 min (69AG(E)212). Preparative resolution has been done both by classical methods, using chiral partners in salts (77DOK(232)108l), and by chromatography on triacetyl cellulose (Section 5.08.2.3.1). 

Graded Adsorbents and Solvents. Materials used in columns for adsorption chromatography are grouped in Table 12 in an approximate order of effectiveness. Other adsorbents sometimes used include barium carbonate, calcium sulfate, calcium phosphate, charcoal (usually mixed with Kieselguhr or other form of diatomaceous earth, for example, the filter aid Celite) and cellulose. The alumina can be prepared in several grades of activity (see below). 

Thrombin (from bovine blood plasma) [9002-04-4] Mj 32,600 [EC 3.4.4.13]. Purified by chromatography on a DEAE-cellulose column, while eluting with O.IM NaCl, pH 7.0, followed by chromatography on Sephadex G-200. Final preparation was free from plasminogen and plasmin. [Yin and Wessler J Biol Chem 243 112 796S.]... 

Technique of thin-layer chromatography. Preparation of the plate. In thin-layer chromatography a variety of coating materials is available, but silica gel is most frequently used. A slurry of the adsorbent (silica gel, cellulose powder, etc.) is spread uniformly over the plate by means of one of the commercial forms of spreader, the recommended thickness of adsorbent layer being 150-250 m. After air-drying overnight, or oven-drying at 80-90 °C for about 30 minutes, it is ready for use. 

Heinz body preparations are positive as Is the heat stability test Electrophoretic examination of hemolysate showed the presence of a fast-moving variant which was readily separated from Hb-A by chromatography on DEAE-Sephadex The abnormal 3- chain was Isolated by CM-Cellulose chromatography as described before, and converted into the S-2-amlnoethyl (AE) derivative... 

Paper chromatography (PC) and thin layer chromatography (TLC) have been used since the 1940s. Preparative PC on Whatman 3 paper, analytical PC on Whatman 1 paper, and analytical TLC on microcrystalline cellulose, silica gel, or polyamide have been applied with a variety of solvents and the behaviors of anthocyanins have been similar in all media. Two-dimensional TLC allows the separation of several compounds and has been nsed to clarify the anthocyanin compositions of different commodities. ... 

---