Papers for chromatography

Paper for chromatography, Whatman (BG002 Schleicher Schuell). 

The experiment could not be simpler Hydrogen cyanide was bubbled through an aqueous solution of NH4OH, the mixture was refluxed overnight and the supernatant was spotted on a filter paper for chromatography. 

Cellulose for chromatography is purified by sequential washing with chloroform, ethanol, water, ethanol, chloroform and acetone. More extensive purification uses aqueous ammonia, water, hydrochloric acid, water, acetone and diethyl ether, followed by drying in a vacuum. Trace metals can be removed from filter paper by washing for several hours with O.IM oxalic or citric acid, followed by repeated washing with distilled water. 

Males et al. [103] used aqueous mobile phase with formic acid for the separation of flavonoids and phenolic acids in the extract of Sambuci flos. In a cited paper, authors listed ten mobile phases with addition of acids used by other investigators for chromatography of polyphenolic material. For micropreparative separation and isolation of antraquinone derivatives (aloine and aloeemodine) from the hardened sap of aloe (Liliaceae family), Wawrzynowicz et al. used 0.5-mm silica precoated plates and isopropanol-methanol-acetic acid as the mobile phase [104]. The addition of small amounts of acid to the mobile phase suppressed the dissociation of acidic groups (phenolic, carboxylic) and thus prevented band diffusions. 

Consumables - filter papers, anti-bumping granules, Soxhlet thimbles and column packings for chromatography. 

The first thing you need is an adsorbant, a porous material that can suck up liquids and solutions. Paper, silica gel, alumina (ultrafine aluminum oxide), corn starch and kitty litter (unused) are all fine adsorbants. Only the first three are used for chromatography. You may or may not need a solid support with these. Paper hangs together, is fairly stiff, and can stand up by itself. Silica gel, alumina, corn starch, and kitty litter are more or less powders and will need a solid support to hold them. 

Cotterill [119] used the soil extraction method devised by McKone [120] in which a 25g sample of soil was extracted with 50ml of methanol by shaking on a wrist-action shaker for lh. The resulting soil slurry was filtered through a Whatman No. 42 filter-paper. For gas chromatography, a 2ml... 

The calibration problem in chromatography and spectroscopy has been resolved over the years with varying success by a wide variety of methods. Calibration graphs have been drawn by hand, by instruments, and by commonly used statistical methods. Each method can be quite accurate when properly used. However, only a few papers, for example ( 1,2,15,16,26 ), show the sophisticated use of a chemometric method that contains high precision regression with total assessment of error. 

Actually, the problem was worked out for chromatography when I was working for Imperial Chemical Industries, but the company had been a bit cautious about letting me publish before and, when I came to write the work up, I made the change to avoid having to submit the paper for permission to publish. 

Electrophoresis A solution of the precipitate was fractionated by preparative paper electrophoresis at pH 1.9 (acetic acid - formic acid buffer). A 30-mg portion of the precipitate was dissolved in 0.45 ml of the buffer and applied s a 20-cm band on the paper (Whatman Chromatography Paper 3 rjj). The sample was chromatographed at 3000 V for 30 min. 

For The Instructor With some batches of TLC plates the solvent front may move too slowly. As an alternative, chromatography paper (Whatman chromatography paper no. 1, 0.016 mm thickness) can be substituted. In this case the solvent front should not be allowed to move farther than 60 mm from the origin. The spotted chromatography paper should be taped with Scotch tape to a glass rod and suspended into the eluting solvent. Be certain that the liquid level is below the spots applied to the paper. The remaining steps are the same. 

The brief historical development in the last chapter noted that the early theoretical papers described chromatography in terms similar to distillation or extraction and were known as the plate theory. Useful as it may have been in the development of chromatography, the plate theory is of little value in modern chromatography and has been replaced by the rate theory. Any of the early books on gas chromatography can be consulted for a discussion of the plate theory, and Giddings1 has written a good historical summary of the concurrent development of the plate and rate theories. 

Paper Chromatography and Radiometry. For chromatography on paper 46 x 57 cm. sheets of Whatman No. 3 filter paper were used. Ten microliters of hydrolyzate or 30 /il. of extract was applied and the chromatograms were developed in the following systems. 

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