Thin-layer chromatographic methods

Inhalation of high concentrations of monochlorotoluenes will cause symptoms of central nervous system depression. Inhalation studies produced an LC q (rat, 4 h) of 7119 ppm for o-chlorotoluene (68). o- and Chlorotoluene are both considered moderately toxic by ingestion (Table 2). A study of the relationship between the electronic stmcture and toxicity parameters for a series of mono-, di-, and tri-chlorotoluenes has been reviewed (72). A thin-layer chromatographic method has been developed to assess the degree of occupational exposure of workers to chlorotoluenes by determining j -cblorobippuric... 

Standard open column and thin-layer chromatographic methods have been gradually replaced by HPLC, which is faster, more reliable, more accurate and highly reproducible for analyzing plant pigments and for opening new perspectives in chlorophyll... 

Washuettl, J., Bancher, E., and Riederer, P., A new thin-layer chromatographic method for determination of caffeine in roasted coffee beans, Zeitschrift fuer Lebensmitteluntersuchung und Forschung, 143,253,1970. 

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. 

Zheng and Sun [67] used a thin-layer chromatographic method for the analysis of primaquine and other quinoline derivatives. The drug and other compounds were chromatographed on silica gel GF254 plate, with methanol aqueous 25 28% ammonia (200 3) and chloroform dichloromethane diethylamine (4 3 1), as mobile phases. Spots were located under ultraviolet radiation. The detection limit was 12 pg/mL. Total separation could be achieved by the use of two plates and the respective mobile phase. 

Gorcharova and Khomenko [127] have described a column chromatographic method for the determination of acetic, propionic, and butyric acids in seawater, and thin-layer chromatographic methods for determining lactic, aconitic, malonic, oxalic, tartaric, citric, and malic acids. The pH of the sample is adjusted to 8 - 9 with sodium hydroxide solution. It is then evaporated almost... 

Whittle [29] has described a thin-layer chromatographic method for the identification of hydrocarbon marker dyes in oil polluted waters. McLeod et al. [25] conducted interlaboratory comparisons of methods for determining traces of aliphatic and aromatic hydrocarbons in marine sediments. Agreement within a factor of 2 to 3 was obtained between the 12 participating laboratories. 

Abbott and Wagstaff [251] of the Laboratory of the Government Chemist UK have described a thin layer chromatographic method for the identification of 12 acidic herbicides and 19 nitrogenous herbicides (carbamates, substituted ureas and triazine). 

M. Gabriels and J. Plaizier-Vercammen, Development of a reversed-phase thin-layer chromatographic method for artemisin and its derivatives. J. Chromatogr. Sci. 42 (2004) 341-347. 

V.P. Kumar, M.N. Ravishankara, H. Padh and M. Rajani, High-performance thin-layer chromatographic method for estimation of rutin in medicinal plants. J. Plan. Chromatogr.—Mod. TLC 16 (2003) 386-389. 

Thin-Layer Chromatographic Methods for the Separation of Benzoic Acid and Other Substances... 

Many thin-layer chromatographic methods have been used for the identification of chlorpromazine [35-53], and for its assay [52, 53,185-187]. The operating conditions associated with these methods are found in Tables 6 and 7, respectively. 

Several thin layer chromatographic methods have been reported that were used for the analysis of procaine [102-114], and selected examples are presented in Table 6. 

Friedman RB, Williams MA, Moser HW, Kolodny EH (1978) Inproved thin-layer chromatographic method in the diagnosis of mannosidosis. Clin Chem 24 1576-1577... 

Sewell AC (1979) An improved thin-layer chromatographic method for urinary oligosaccharide screening. Clin Chim Acta 92 411-414... 

The low-molecular-weight water-soluble fraction of LCP flour was found by thin layer chromatographic methods to contain several flavonoid components. To establish the role of flavonoids in the production of yellow color in biscuits, these components were extracted from LCP and glandless cottonseed flours with 85Z aqueous isopropyl alcohol (which is a better solvent for flavonoids than water). Before removal of the flavonoids, the flours had been treated with petroleum ether to extract residual lipids that could interfere with flavonoid isolation. Extraction of the residual lipids did not significantly alter the color of biscuits prepared with the extracted flours (Figure 7). 

THIN-LAYER CHROMATOGRAPHIC METHODS Four amino- Animal MeOH cleanup,... 

In thin-layer chromatographic methods, sulfonamide residues were first separated on commercially available silica gel plates using various solvent mixtures as mobile phase, and subsequently detected by fluorometry after spraying... 

Thin-layer chromatographic methods are limited to the determination of hygromycin B and have been carried out on commercially available silica gel... 

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