Cellulose thin-layer plates

The simplest form of liquid-liquid chromatography is paper chromatography (or commercially prepared cellulose thin-layer plates) in which the... 

Cellulose is itself polar in nature and can cause some adsorption, which may result in the tailing of zones. However, this adsorptive effect may contribute to the separation process in some instances and the use of a polar mobile phase can enhance this effect further, e.g. the separation of amino acids using an aqueous solution of ammonia as the mobile phase. The combination of partition and adsorption generally influences separations on cellulose thin-layer plates, which have superseded paper chromatography in most instances and offer increased speed and resolution. 

Figure 2. Tryptide analyses of poliovirus NCTPx, and a I40 kU apparent precursor to NCVPx. Bona fide poliovirus (55s) NCVPx (gel l) was isolated, and its tryptic map compared with that of the I40 kB protein isolated in zinc (0.5 mM)-treated infected cells (gel II) by two-dimensional electrophoresis (pH 2.1) and chromatography (butanol acetic acid water, 3 1 1) on cellulose thin layer plates. Other tryptic fragments in the I40 kD protein are present in poliovirus coat proteins (not shown).

Phosphopeptide Mapping and Phosphoamino Acid Anaiysis on Cellulose Thin-Layer Plates... 

Boyle, W. J., van der Geer, P., and Hunter, T. (1991b) Phosphopeptide mapping and phos-phoamino acid analysis by two-dimensional separation on cellulose thin-layer plates. In Methods in Enzymology (T. Hunter and B. M. Sefton, eds.), Vol. 201, pp. 110-149. Academic Press, San Diego. 

IV. ENANTIOMERIC SEPARATIONS ON CELLULOSE THIN-LAYER PLATES... 

Solvent systems (a) 80per cent formic acid-metahmol-HCl (80 15 0.5) (b) collidine-lutidin-water (1 1 2) (c) collidine-water (3 1) all by volume. The pre-coated thin-layer plates were silica gel and cellulose. 

E. Merck cellulose thin-layer chromatography plates (available from American Scientific Products) are developed with chromatography buffer (Note 13) and visualized with sulfosalicylic acid/ferric chloride spray. The system consists of a solution of 1.0 g of sulfosal icyl ic acid (from Aldrich... 

Solvent systems used for thin layer chromatography were 1) n-butanol acetic acidiwater (4 1 5 upper phase), 2) acetic acid water (15 85), 3) ethyl acetate pyridine water (12 5 4), and 4) chloroform acetic acid water (50 45 5). Silica gel plates were used for chromatography of flavonoid aglycones and cellulose plates for all other components. Aluminum chloride was used for detection (under long UV light) of flavonoids, aniline phthalate for sugars, ninhydrin for amino acids and iodine for other components. Cellulose thick layer plates were developed with solvents 1 or 2. 

The support medium may be a sheet of cellulose or a glass or plastic plate covered with a thin coating of silica gel, alumina, or cellulose. Large sheets of cellulose chromatography paper are available in different porosities. These may be cut to the appropriate size and used without further treatment. The paper should never be handled with bare fingers. Although thin-layer plates can easily be prepared, it is much more convenient to purchase ready-made plates. These are available in a variety of sizes, materials, and thicknesses of stationary support. They are relatively inexpensive and have a more uniform support thickness than hand-made plates. 

Vovk I, Simonovska B and Vuorela H, Separation of eight selected flavan-3-ols on cellulose thin-layer chromatographic plates. J Chromatogr A 1077 188-194 (2005). 

Rump [17] has described a cellulose thin layer method for the detection of phenolic acids such as iw-hydroxybenzoic acid, iw-hydroxyphenylacetic acid and m-hydroxyphenylpropionic acid, in water samples suspected to be contaminated with liquid manure. The phenolic acid is extracted with ethyl acetate from a volume of acidified sample equalling lmg of oxygen consumed (measured with potassium permanganate). The ethyl acetate is evaporated and the residue dissolved in ethanol. After spotting of a lpm aliquot on a cellulose plate the chromatogram is developed by capillary ascent with the solvent n-propanol-w-butanol-25% NH3-water (4 4 1 1 by vol). The solvent front is allowed to advance 10cm. The air-dried plate is sprayed with a diazotised p-nitroanilinc reagent to make the phenolic acids visible. 

PEI-thin layer plates Plastic sheets coated with PEI (polyethylene-imine)-cellulose for thin-layer chromatography. 20 x 20 cm sheets Polygram CEL 300 PEI/UV254 obtainable from Macherey-Nagel Co., 516 Diiren, Werkstrasse, 6-8, Postfach 307, West Germany or from laboratory suppliers. 

When formed on cellulose [thin-layer-chromatography (TLC) plates], the colored forms of 6-nitro-8-methoxyBIPS and of trimethylindolinospironaphthoxa-zine are stabilized against thermal or photoerasure by interaction with nickel or zinc salts of hydroxy carboxylic acids or dicarboxylic acids. The zinc salts of 1-hydroxy-... 

In paper chromatography we use filter paper, marketed for this purpose. It comes usually in the form of a 2-5 cm-wide tape, from which a strip of the necessary length can easily be cut. The more modern technique of thin layer chromatography (TLC), makes use of thin sheets of aluminium oxide, silica-gel, cellulose or some other material, supported by a metal sheet or a polymer. Chromatographic thin layers can be prepared in the laboratory from commercially available adsorbents. A thick suspension of these is made with water (usually a 2 1 w/w mixture of water adsorbent is made up) and this is then spread on a metal plate with a suitable spreader device. Techniques vary from device to device, and the instructions of the manufacturer should be followed whenever thin layer plates are to be prepared. Ready-made thin layer sheets are also available commercially. These contain the active material spread on a plastic support. Thin-layer chromatographic materials, especially ready-made plates, are much more expensive than chromatographic paper, but normally offer faster and sharper separations than the paper. The procedures described in Section VI.20 can be carried out both on a slow chromatographic paper (e.g. Whatman No. 1) or on a cellulose thin layer (e.g. Whatman cellulose). 

Several acidic solvent systems and types of supports work with varying efficiency (Table 23). Cellulose and silica gel H (with organic binder) allow the movement of arsenite, but arsenate and disodium methanearsonate (DSMA) remain on the origin. DSMA, arsenate and arsenite separate best on thin-layer plates coated with silica gel G (calcium sulphate binder). 

Farrelly and Watkins (F4) have used high voltage electrophoresis of unmodified urine or deproteinized serum for the rapid separation of fourteen amino acids in one direction on a thin-layer plate. Evered and Dando (E16) have employed low voltage electrophoresis for one way separation of amino acids on Whatman No. 1 paper using various buffer solutions. They stated that only the acidic and basic amino acids, p-amino acids, and cystine could be separated completely from a complex mixture such as blood or urine. Scherr (SIO) and Stevens (S52) have also used low voltage electrophoresis for the unidirectional separation of amino acid mixtures on cellulose acetate strips. 

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