Chromatographic adsorption

As stated earlier, these hydrocarbons are difficult to quantify with accuracy. The FIA method, which is a chromatographic adsorption on silica, gives volume percentages of saturated hydrocarbons, olefins and aromatics. 

The chief uses of chromatographic adsorption include (i) resolution of mixtures into their components (Li) purification of substances (including technical products from their contaminants) (iii) determination of the homogeneity of chemical substances (iv) comparison of substances suspected of being identical (v) concentration of materials from dilute solutions (e.g., from a natural source) (vi) quantita tive separation of one or more constituents from a complex mixture and (vii) identi-1 ig- II, 16, 3. gcajjQij and control of technical products. For further details, the student is referred to specialised works on the subject. ... 

See, for example, A. Weiseberger (Editor), Technique of Organic Chemistry. Volume V. Adsorption and Chromatography. Interacience (1951) H. H. Strain, Chromatographic Adsorption Analysis, Interacience (1945). 

It is important to appreciate clearly the function of solvents in chromatographic adsorption. Whereas in any one analysis only one adsorbent will normally be employed, several solvents may be used. Solvents have a triple role —... 

An account of the general technique of chromatographic adsorption has been given in Section 11,46. The simple applications to be described are —... 

Application of Snyder s theory of linear chromatographic adsorption (171) gives the variation in adsorption energy of the thiazole nitrogen atom as a function of this steric hindrance for silica and alumina (see Table III-22). These results show that alumina is more sensitive toward steric effects while silica shows a higher selectivity in the case of polar effects. 

Vz grams of the residue were dissolved in 10 ml of benzene, and the solution was passed over a chromatographic adsorption column containing 50 grams of alumina (Alcoa activated alumina. Grade F-20) which had previousiy been shaken for about 20 minutes with a mixture of 100 ml of benzene containing 1.5 ml of 10% acetic acid. 

Chromatography of Nonsaponifiable Lipids. The nonsaponifiable residue plus 4.5 mg. of carrier cholesterol was applied to the top of a 7.5 X 1.7 cm. column containing 20 grams of Merck alumina (suitable for chromatographic adsorption) which had been previously deactivated by mixing with 7% aqueous acetic acid (10% glacial acetic acid in distilled water) (18). The column was packed in petroleum ether (redistilled, b.p. 60-70° C.) and 10 ml. fractions were collected. The eluting solvents are shown in Table II. 

A platinum on silica gel catalyst was prepared by impregnation of silica gel (BDH, for chromatographic adsorption) by a solution containing 0.5% (wt.) of sodium hydroxide and 0.5% (wt.) of chloroplatinic acid (both of analytical grade). The dried catalyst contained 1% (wt.) of platinum and a corresponding amount of the alkaline component. The BET surface area of the catalyst was 40 m2/g, the mean pore radius 150 A. The catalyst was always reduced directly in the reactor in a stream of hydrogen at 200°C for 2 hr. 

A platinum-iron on silica gel catalyst was prepared by impregnating silica gel (BDH, for chromatographic adsorption) with an aqueous solution of chloroplatinic acid (analytical grade) and sodium hydroxide (analytical grade). The dry product was then impregnated by a ferrous sulfate solution (C.P. grade) and the water was removed in a rotating evaporator. The prepared catalyst contained 1% Pt, 0.7% Fe, and 2% NaOH (by... 

Vol. 2 Chromatographic Adsorption Analysis. By Harold H. Strain (out of print)... 

The hydrolysis products of methylated disaccharides may be separated by p-phenylazobenzoylation followed by chromatographic adsorption, or the methanolysis products of the methylated disaccharides may be separated due to differential water solubilities of the p-phenylazo-benzoates.110... 

Various fully-acetylated monosaccharides and disaccharides or sugar alcohols are readily separable by chromatographic adsorption on Mag-nesol (a hydrated magnesium acid silicate)111 and the unacetylated substances may be separated on clay columns.112... 

AV reciprocating tachycardia, 5 108 Axial dispersion coefficient, 10 762 Axial dispersion/mixing, 10 762-763 in adsorption columns, 2 604 in bubble tray absorbers, 2 88-89 chromatographic adsorption, 2 610 in packed column absorbers, 2 61-65 Axial dissolved oxygen profiles, 25 707-708 Axial filtration, 22 385-386 Axial-flow angular-momentum flowmeter, 22 672-673... 

Chromatographic Adsorption of Pigment from Leaves.2—Immerse fresh leaves (3-4) of spinach in a mixture of 45 c.c. of petrol ether (boiling point 70°), 5 c.c. of benzene and 15 c.c. of methanol in a conical flask. Leave for one hour, remove the almost white residue by filtration at the pump, and wash with the same mixture of solvents. Transfer the liquid to a separating funnel and without shaking remove the methyl alcohol completely by repeated cautious washing with water. Then dry the solution over sodium sulphate. 

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