Thin-layer chromatography on silica gel

Bismethylaminoanthraquinone (Disperse Blue 14) [2475-44-7] M 266.3, A,max 640 (594)nm. Purified by thin-layer chromatography on silica gel plates, using toluene/acetone (3.1) as eluent. The main band was scraped off and extracted with MeOH. The solvent was evapd and the dye was dried in a drying pistol [Land, McAlpine, Sinclair and Truscott J Chem Soc, Faraday Trans I 72 2091 7976]. 

The resulting product is purified by thin layer chromatography on silica gel in methylene dichloride yielding 8)S-di-5a-cholestane-3,6-dione (162) 13 mg, overall yield 26% mp 160-164°, which consists of 83% of dj-species. 

Fractions may be monitored by thin-layer chromatography on silica gel, developing with 10% v/v ethyl acetate in hexane and visualizing with iodine vapor. The following Rf values were observed famesol, 0.07 farnesyl acetate, 0.35 bromohydrin acetate, 0.20. 

A three-step nitration process of toluene is described. The advantages of the modified process are reduced waste, less hazardous operation, reduced oleum requirement, partial replacement of coned HN03 with dil HN03, and higher rate of toluene flow into the reactor (Ref 86) The continuous process of H.C. Prime (Ref 73) for preparing TNT was studied by thin-layer chromatography on silica gel with a starch binder and a fluorescent indicator. The nitration... 

Olefins, sultones, alkanes, and alkenesulfonates may be separated by liquid chromatography on silica gel using hexane, trichloromethane-hexane, ethanol-dime thy lcarbonate, and ethanol-ammonium hydroxide as the eluents. Pueschel and Prescher [110] achieved the separation of alkene-1,4-sultone and alkene-1,3-sultone from each other and from other sulfonic acid esters in AOS by thin-layer chromatography on silica gel G with 4 1 diethylcarbonate-ligroine as the... 

Besides the calculation of the different sulfonated species, it is also possible to determine them directly by chromatographic methods. Separation of the ester sulfonate and the disodium salt is achieved by thin-layer chromatography on silica gel plates. With a solvent mixture of acetone and tetrahydrofuran (90 10 v/v) the disodium salt stays at the start whereas the ester sulfonate has an R value of 0.2. With the more polar solvent 0.1 N H2S04 + methanol + chloroform the ester sulfonate and the disalt have Rf values of 0.36 and 0.14. For visualization, the plate is sprayed with pinacryptol yellow. In UV light (254 and... 

Chedid, A. Haux, P. and Natelson, S. Use of thin layer chromatography on silica gel for serum lipid fractionation and measurement in the routine clinical laboratory. Clin. Chem. (1972), 13, 384 - 390. 

Chromatographic characterisation of hydrolysis products Hydrolysis products from sodium polypectate were analysed by thin-layer chromatography on silica gel G-60, using ethyl acetate / acetic acid / formic acid / water (9 3 1 4, by volume) as the mobile phase system. Sugars were detected with 0,2% orcinol in sulphuric add-methanol (10 90ml) [14]. 

Caffeine was extracted from ficw varieties of roasted coffee beans and was determined in parallel by (1) measurement of spot area after thin layer chromatography on silica gel GF plates (development with chloroform/ cyclohexane/glacial acetic acid, 8 2 1, visualization in UV light), and (2) Kjeldahl N determination. Caffeine contents by (1) and (2), respectively, in the five varieties analyzed were (percent in DM) Santos lave 0, 1.10, and 1.12 Java Robusta 3, 1.19, and 1.22 Camerun Robusta 2, 1.16, and 1.19 Mocca 2, 1.21, and 1.26 Guatemala 0, 1.18, and 1.20. (1) is considered slightly less accurate than (2) but rather easier and more rapid.21... 

Van de Vaart et al. [45] used a thin-layer chromatographic method for the analysis of miconazole and other compounds in pharmaceutical creams. The drugs in creams were analyzed by thin-layer chromatography on silica gel plates with ether in pentane-saturated chamber or with butanol-water-acetic acid (20 5 2). Both active ingredients and vehicle components were detected and Rf values of 67 active ingredients are tabulated. Additional eluents may be needed to separate certain combinations of ingredients. 

The consumption of the oxime can be checked by thin-layer chromatography on silica gel G with the solvent system chloro-form/methanol (95/5 v/v) and a spray reagent consisting of 5% potassium dichromate in 40% sulfuric acid. The oxime appears as an immediate dark spot and the aziridine as a yellow spot. The checkers observed identical mobilities (Rf 0.8) for both compounds. 

Smith and coworkers152 published a relatively complete paper on the thin-layer chromatography, on silica gel, of carbohydrates of low molecular weight. Bancher and coworkers153 reported the thin-layer chromatography of degradation products of carbohydrates, including aldonic acids and aldonolactones. 

N-methylcarbamate and N,N -dimethylcarbamates have been determined in soil samples by hydrolyses with sodium bicarbonate and the resulting amines reacted with 4-chloro-7-nitrobenzo-2,l,3-Oxadiazole in isobutyl methyl ketone solution to produce fluorescent derivatives [81]. These derivatives were separated by thin layer chromatography on silica gel G or alumina with tetrahydrofuran-chloroform (1 49) as solvent. The fluorescence is then measured in situ (excitation at 436 nm, emission at 528 and 537nm for the derivatives of methylamine and dimethylamine respectively). The... 

Although the metabolism of several phthalate esters has been studied in vitro, essentially all of the in vivo studies have involved DEHP. A summary of these experiments which involved exposure offish to aqueous - C-DEHP is presented in Table IV (11,12). Tissue C was isolated and separated into parent and the various metabolites by preparative thin layer chromatography on silica gel. Metabolites were hydrolyzed where appropriate and identified by gas chromatography-mass spectroscopy. In whole catfish, whole fathead minnow and trout muscle, the major metabolite was the monoester while in trout bile the major metabolite was the monoester glucuronide. The fact that in all cases the major metabolite was monoester or monoester glucuronide despite the differences in species, exposure level and duration, etc. represented by these data, suggests that hydrolysis of DEHP to monoester is important in the biotransformation of DEHP by fish. 

The soluble metabolites excreted from animals dosed by injection were collected on AmberliteR XAD-4 resin, the resin eluted sequentially with diethyl ether, acetone, and methanol, and the solutes separated by thin-layer chromatography on silica gel and quantitated by liquid scintillation counting. 

The precipitate was filtered off, washed with ether, and dried under vacuum to yield 4.7 g of dry product (A-poly-2). Thin layer chromatography on silica gel using dichloromethane/methanol (93 7) showed only a trace of free monomer. This activated copolymer was soluble in water, THF, CH2CI2 and DMF. It was reproducibly prepared in good quantity and stored in the solid state for months, protected from moisture, without loss of activity. 

Following extraction/cleanup, quinoxaline-2-carboxylic acid can be detected by electron capture, or mass spectrometric techniques, after gas chromatographic separation on capillary or conventional columns. A prerequisite of quin-oxaline-2-carboxylic acid analysis by gas chromatography is the derivatization of the molecule by means of esterification. Esterification has been accomplished with methanol (419, 420, 422), ethanol (421), or propanol (423) under sulfuric acid catalysis. Further purification of the alkyl ester derivative with solid-phase extraction on a silica gel column (422), thin-layer chromatography on silica gel plate (420), or liquid chromatography on Hypersil-ODS, 3 m, column (423), has been reported. 

Once several silica gel column fractions have been collected, the eluted fractions must be analyzed for the presence of lipids. Thin-layer chromatography on silica gel plates will be introduced in this experiment for the detection and identification of neutral lipids. 

Analysis of the purity of each silica gel column fraction and classification of the unknown lipid can be accomplished by thin-layer chromatography on silica gel plates. On a single plate will be spotted (1) a solution of the crude lipid extract from part A, (2) aliquots from each lipid fraction of the column (or recrystallized lipid), and (3) solutions of standard lipids (listed in the Materials section). On a 20 X 20 cm silica gel plate there is room for nine different analyses. Prepare a 1% solution of the crude lipid from part A in chloroform (10 mg/1 mL). If recrystallized lipid is to be... 

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