Thin-layer chromatography analysis

The benzene layer is removed by decantation and the remaining mixture is rendered basic with 10% sodium hydroxide solution and is extracted with three 1,500 ml portions of benzene. The benzene extracts are washed, then dried with anhydrous sodium sulfate and concentrated in a vacuum leaving a residue of 1,530 grams, gas and thin layer chromatography analysis show this to be a cis/trans mixture (approx. 4 1) of 11-dimethylamino-propylidene-6,11-dihydrodibenz-(b,e)oxepin (90% yield). This mixture has substantially more activity pharmacologically than the cis/trans mixture obtained by the Grignard route disclosed in the Belgian Patent 641,498. This base is then converted to the hydrochloride with HCI. 

Marutoiu C, Sarbu C, Vlassa M, et al. 1986. A new separation and identification method of some organophosphorus pesticide by means of temperature programming gradient thin-layer chromatography. Analysis 14 95-98. 

Clark et al. [53] subjected primaquine to metabolic studies using microorganisms. A total of 77 microorganisms were evaluated for their ability to metabolize primaquine, of these, 23 were found to convert primaquine to one or more metabolites (thin-layer chromatography analysis). Preparative scale fermentation of primaquine with four different microorganisms resulted in the isolation of two metabolites, identified as 8-(3-carboxy-l-methylpropylamino)-6-methoxyquinoline and 8-(4-acetamido-l-methylbutylamino)-6-methoxyquinoline. The structures of the metabolites were proposed, based primarily on a comparison of the 13C NMR spectra of the acetamido metabolite and the methyl ester of the carboxy metabolite with that of primaquine. The structures of both metabolites were confirmed by direct comparison with authentic samples. 

Experiment 38 The Thin-Layer Chromatography Analysis of Cough Syrups for Dyes... 

B. General Oxidation Procedure for Alcohols. A sufficient quantity of a 5% solution of dipyridine chromium (VI) oxide (Note 1) in anhydrous dichloromethane (Note 7) is prepared to provide a sixfold molar ratio of complex to alcohol. This excess is usually required for complete oxidation to the aldehyde. The freshly prepared, pure complex dissolves completely in dichloromethane at 25° at 5% concentration to give a deep red solution, but solutions usually contain small amounts of brown, insoluble material when prepared from crude complex (Note 8). The alcohol, either pure or as a solution in anhydrous methylene chloride, is added to the red solution in one portion with stirring at room temperature or lower. The oxidation of unhindered primary (and secondary) alcohols proceeds to completion within 5 minutes to 15 minutes at 25° with deposition of brownish-black, polymeric, reduced chromium-pyridine products (Note 9). When deposition of reduced chromium compounds is complete (monitoring the reaction by gas chromatography or thin-layer chromatography analysis is helpful), the supernatant liquid is decanted from the (usually tarry) precipitate and the precipitate is rinsed thoroughly with dichloromethane (Note 10). 

Seeboth, H., Thin-layer chromatography analysis of phenols, Monatsber. Deut. Akad. Wiss. Berl., 5, 693, 1963 Chem. Abs., 61, 2489c, 1964. 

A. S. Kenyon, P. E. Flinn, and T. P. Layloff, Rapid screening of pharmaceuticals by thin-layer chromatography Analysis of essential drugs by visual methods, J. AOACInt., 78 41 (1995). 

Figure 31.6. Thin layer chromatography analysis of products from the bioconversion of fatty acids by P. aeruginosa PR3. Lane numbers consecutively represented standard docosahexaenoic acid (DHA), bio-converted DHA, standard eicosapentaenoic acid (EPA), bio-converted EPA, standard conjugated linoleic acid (CLA), bio-converted CLA, standard linoleic acid (LA), and bio-converted LA.

Measure the volume of the dichloromethane in a dry graduated cylinder, place exactly one-fifth of the solution in a tared Erlenmeyer flask, add a wood boiling stick (easier to remove than a boiling chip), and evaporate the solution on a steam bath in a hood. The residue of crude clove oil will be used in the thin-layer chromatography analysis. From its weight, the total yield of crude clove oil can be calculated. 

Thin-Layer Chromatography Analysis of Analgesics and Isolation of Lycopene from Tomato Paste... 

Cover 0.5 g of cholesterol with 5 mL of acetic acid in a small Erlenmeyer flask, swirl, and note that the initially thin slurry soon sets to a stiff paste of the molecular compound C27H45OH CH3CO2H. Add 1 mL of acetic anhydride and heat the mixture on the steam bath for any convenient period of time from 15 min to 1 h record the actual heating period. While the reaction takes place, prepare the chromatographic column. Cool, add 20 mL of water, and extract with two 25-mL portions of ether. Wash the combined ethereal extracts twice with 15-mL portions of water and once with 25 mL of 10% sodium hydroxide, dry by shaking the ether extracts with 25 mL of saturated sodium chloride solution, then dry the ether over anhydrous sodium sulfate for 10 min in an Erlenmeyer flask, filter, and evaporate the ether. Save a few crystals of this material for TLC (thin-layer chromatography) analysis. Dissolve the residue in 3-4 mL of ether, transfer the solution with a capillary dropping tube onto a column of 12.5 g of silica gel, and rinse the flask with another small portion of ether. ... 

The specificity of PSPBP to PSP extracted from A. tuberculatum was determined by thin layer chromatography analysis whish shows a delay of migration of the complex PSPBP-PSP compared to the PBPSP alone. This delay is probably due to the binding of the PSP on PSPBP (Figure 6). 

Thin-Layer Chromatography Analysis of Herbal Drug Mixtures. 355... 

ToddjJ.S. 1969. Thin-layer chromatography analysis of Mexican population of... 

Sherma, J, Harnett, H. D., and Jain, A. V. (I 99). Thin layer chromatography analysis of dialtcyl phosphate degradation products of organophosphorous pesticides on C-18 chemically bonded phases. 7. Liquid Chmmatogr Ret. Technol. 22.137-141. 

Flinn, P.E. Juhl, Y.H. Layloff, T.P. A simple, inexpensive thin layer chromatography method for the analysis of theophylline tablets. BuU. World Hlth. Org. 1989,67, 555-559. Flinn, P.E. Kenyon, A.S. Layloff, T.P. A simplified TLC system for qualitative and semiquantitative analysis of pharmaceuticals. J. Liquid Chromatogr. 1992,15, 1639-1653. Kenyon, A.S. Flinn, PJi. Layloff, T.P. Rapid screening of pharmaceuticals hy thin layer chromatography Analysis of essential dmgs hy visual methods. J. AOAC Inti. 1995, 78, 41 9. 

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