Thin layer chromatography spray reagents

Patil VB, Sevaikar MT, Padalikar SV. 1987. Specific spray reagent for the detection of endosulfan by thin-layer chromatography. J Chromatogr 396 441-443. 

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. 

Thin layer chromatography was carried out on 20x20cm glass plates coated 0.25mm thick with a suitable support and dried overnight. Silica gel G, silica gel H and cellulose were examined as the solid phases for chromatography of methanearsonate, arsenite and arsenate. Several sprays for the visualization of the arsenicals on plates were tested. Three of the more successful reagents and the colour produced with final product are shown in Table 13.2. 

Color reactions are used in the laboratory in conjunction with thin-layer chromatography (TLC) — a routine and highly popular method for the analysis of explosives (for a full review, see Ref. [1, chapter 5, pp. 59—85] and Ref [2, chapter 2, pp. 33—41]). Spots on the TLC plates are visuaHzed by spraying the plates with appropriate color reagents. 

Early applications of thin-layer chromatography in corticosteroid analysis were mainly based on use of phenylhydrazine in sulfuric acid as a spray reagent for derivatization of the analytes (529, 530). Later applications involved use of other spray reagents including phosphoric acid in methanol, tetrazolium blue. 

Modification of the Activity of Alumina by Addition of Water Stationary and Mobile Phases Typical Stationary and Mobile Phase Systems Used in the Separation of Various Inorganic Ions Spray Reagents in Thin-Layer Chromatography Protocol for Reagent Preparation... 

Krebs, K.G., Heusser, D., and Wimmer, H., Spray reagents, in Thin Layer Chromatography, A Laboratory Handbook, Stahl, E., Ed., Springer-Verlag, New York, 1969, p. 854. 

Spray Reagents in Thin-Layer Chromatography (continued)... 

The following section gives a summary for the preparation of the major spray reagents listed in the previous section (Spray Reagents in Thin-Layer Chromatography). Refer to the original literature for any reagents not listed here.1 4... 

B. Basak, U. K. Bhattacharyya, and S. Laskar, Spray reagent for the detection of amino acids on thin layer chromatography plates, Amino Acids, 4 193(1993). 

Eugenol can be determined in mixtures with myristicin, apiol, allyltetramethoxybenzene, and elemicin using thin layer chromatography [23]. The method uses silica gel as the stationary phase, and 97 3 toluene-ethyl acetate as the mobile phase. Detection is effected on the basis of the UV absorbance at 254 nm, and by spraying with vanillin-sulfuric acid reagent. 

Thielemann [115] discussed the determination of hydroquinone and its oxidation product 1,4-benzoquinone, both of which are toxic constituents of coal industry waste water. He reviews methods for the quantitative detection of benzoquinone and describes a semiquantitative method for its determination by thin layer chromatography on Kieselgel G using 2% ethanolic solution of 4-aminoantipyrine (l-phenyl-2,3-dimethyl-4-aminopyrazol-5-one) as spray reagent. 

It is best to purify the methyl esters by thin-layer chromatography of the sample on another silica gel G (250 p,m) plate using this solvent system, but without any spray reagent being used. A comparable plate is run and the methyl ester band is detected by the sulfuric acid/char reaction. Then the unsprayed plate is scraped at the methyl ester area and the silica gel is extracted with petroleum-diethyl ether (80 20, v/v) or with chloroform-methanol-water (1 2 0.8, v/v). It is always prudent to spray the latter plate (after removing the desired area by scraping) with sulfuric acid and then charring. This will validate whether the apparent removal of all of the methyl esters has been accomplished. 

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