Chromatographic analysis thin-layer

Crude methyl 2-bromostearate (33 g, 0 087 mol) is dissolved in 200 mL of acetonitrile containing 0 5 mL of water, and silver(I) fluonde (50 g, 0 393 mol) is added rapidly in one portion The slurry is stirred vigorously for 20 h in an oil bath at 80 C At the end ot this time thin-layer chromatographic analysis (petroleum... 

E. Menziani, B. Tosi, A. Bonora, P. Reschiglian and G. Eodi, Automated multiple development high-performance thin-layer chromatographic analysis of natural phenolic compounds , 7. Chromatogr. 511 396-401 (1990). 

The checkers found that a fraction, b.p. 45-71° (18 mm.), had the following spectral properties infrared (carbon tetrachloride) no absorption in the 3300-1600 cm.-1 region attributable to OH, C=0, or C=C vibrations proton magnetic resonance (chloroform-d) <5, multiplicity, number of protons, assignment 3.1-4.2 (multiplet, 4, CH—Cl, CH—O, and C//2—O), 1.0-2.5 (multiplet, 7, GH3 and 2 x C//2)-Thin layer chromatographic analysis of this fraction on silica gel plates using chloroform as eluent indicated the presence of a major component (the cis- and fraus-isomers), Rf = 0.60, and a minor unidentified component, Rf = 0.14. 

ASTM Standard D 3156-81, Thin-layer Chromatographic Analysis of Antidegradants (Stabilizers, Antioxidants and Antiozonants) in Raw and Vulcanized Rubbers, Annual Book of ASTM Standards, ASTM, Philadelphia, PA (1990). 

A variety of procedures were utilized to analyze this reaction mixture and to characterize a,10-diaminopolystyrene. Thin layer chromatographic analysis using toluene as eluent exhibited three spots with Rf values of 0.85, 0.09, and 0.05 which corresponded to polystyrene, poly(styryl)amine and a,w-diaminopolystyrene (see Figure 1). Pure samples of each of these products were obtained by silica gel column Chromatography of the crude reaction mixture initially using toluene as eluent [for polystyrene and poly(styryl)amine] followed by a methanol/toluene mixture (5/100 v/v) for the diamine. Size-exclusion chromatography could not be used to characterize the diamine since no peak was observed for this material, apparently because of the complication of physical adsorption to the column packing material. Therefore, the dibenzoyl derivative (eq. 5) was prepared and used for most of the analytical characterizations. 

TLC Analysis. For experiment 2, thin layer chromatographic analysis was carried out by reducing solvent volumes to less than 250 pi under a nitrogen stream, spotting on activated silica gel plates, and developing in chloroform acetone (20 1, v v). Autoradiographs of these plates were prepared by exposing them to X-ray film for 3 or 4 days at -20 C. 

Further thin layer chromatographic analysis of the toxic fraction indicated a three component system with the major toxic component moving just off of the origin (Rf = 0.05) and two lightly detectable, non-toxic components occurring at Rf s 0.6 and 0.63. 

Thin layer chromatographic analysis at this stage shows that 1-phenylthio-2-bromoethane is absent. 

Thin-layer chromatographic analysis of the product by the submitter... 

The product is pure by thin-layer chromatographic analysis (Alumina GF Uniplate from Analtec, Inc., 1 1 ethyl acetate hexane solvent, Rf = 0.79) and 1H NMR... 

Thin layer chromatographic analysis of 4-acetoxyazetid1n-2-one was carried out on E. Merck Silica gel F254 plates by elution with ethyl acetate. The hexane-soluble impurity (Rf 0.67) was detected by shortwave UV. 4-Acetoxyazetidin-2-one (Rf 0.38) was detected by exposure of the plate for 5 min to chlorine gas followed by spraying with TDM solution (Note 9) and heating with a hot air gun. 

Avigad, G., Dansyl hydrazine as a fluorimetric reagent for thin-layer chromatographic analysis of... 

Kasang G. and Weiss N. (1974) Thin layer chromatographic analysis of radioactively labelled insect pheromones. Metabolites of [3H]bombykol. J. Chromatog. 92, 401-417. 

A mixture of 3.44 g (9.63 mmoles) of 4-(2-di-n-propylaminoethyl)-7-hydroxy-2(3H)-indolone hydrobromide (U. S. Pat. No. 4,314,944), 22 cc of dimethylformamide, 1.79 g (9.91 mmoles) of 5-chloro-l-phenyl-lH-tetrazole, 220 cc of acetone, 10 cc of water and 2.90 g (21 mmoles) of anhydrous potassium carbonate was refluxed for about 3 hours at which time thin layer chromatographic analysis (silica gel GF, 75-23-2 ethyl acetate-methanol-conc. ammonium hydroxide) indicated that the reaction was complete. 

It seems that the product is expectedly divided into three fractions by this chromatography. Thin-layer chromatographic analysis for the fractions of the graft copolymer indicates that each fraction is not contaminated by more than 0.5—1 wt% with either homopolymer. This contamination could be decreased if the elutions... 

Alkaloids of Aconitum confertiflorum Monoacetyltalatisamine.—The tubers of A. confertiflorum (DC.) Voroschilov were extracted with dichloroethane to yield 1.98% of total alkaloids.12 Thin-layer chromatographic analysis indicated that this alkaloid fraction contained at least nine components. Two of the bases were isolated by column chromatography on aluminium oxide. The first alkaloid was an amorphous base, reported to be a monoacetyltalatisamine (4). Neither structure... 

Thin layer chromatographic analysis of 4-acetoxyazet1d1n-2-one was carried out on E. Merck Silica gel F254 plates by elution with ethyl... 

Golden, G. M. et al. Comparison of skin permeability and thin layer chromatographic analysis of lipids isolated from various stratum comeum. Journal of Investigative Dermatology 98 642,1992. 

Fig. 1 Schematic diagram of the steps in a thin layer chromatographic analysis. (Adapted from Camag Scientific, Inc.)...

Spectroscopic analysis did not appear to be suitable. Thin layer chromatographic analysis is useful and may be used to differentiate among the major groups of gums. However, under the best of circumstances it is only semiquantitative. We settled upon gas-liquid partition chromatography (GLC) of the hydrolysate as the best method of identification, as it provides the best information on the monosaccharide profile, in lieu... 

Spectroscopic and thin layer chromatographic analysis has shown that, even when not found in the final product, epoxides are present during the reaction of such pinacols as I,l,2,2-ictraphenyl-l,2-ethanediol. It seems most likely that epoxides represent a blind alley down which many molecules stray before pinacolone is finally formed, (a) How are these epoxides probably formed (b) What probably happens to them in the reaction medium ... 

A simple and fast method for identification of bifidobacteria using thin layer chromatographic analysis of short chain fatty acids in a culture broth is proposed (Table 1). This approach has many advantages the total time required to analyze organic acids is approximately 50 min and the identification protocol is simpler, quicker, and more economical than conventional identification methods. 

Thin layer chromatographic analysis is also highly applicable to the determination of aromatic organic acids.In human organisms, aromatic acids are synthesized as metabolites in intoxication by toluene, xylene, and ethyl benzene. These compounds are easily absorbed through the skin or respiratory system, and are oxidized to aromatic acids. The separation, identification, and quantitative analyses of aromatic acids are also necessary because they appear as semiproducts of the biosynthesis of aromatic amino acids in plants (phenolic acids), and metabolites of numerous toxic substances, drugs, and catecholamines. Polar adsorbents and polar-... 

Leite, C.Q.F. Desouza, C.W.O. Leite, S.R.D. Identification of mycohacteria hy thin layer chromatographic analysis of mycolic acids and conventional hiochemical method—Four years of experience. Mem. Inst. Oswaldo Cruz 1998, 93 (6), 801-805. 

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