Showing papers on "Thin-layer chromatography published in 1993"
TL;DR: High performance thin layer chromatography (HPTLC) is an improved technique for screening lichen substances and it is shown that it can improve the quality of results and reduce the number of errors.
Abstract: High performance thin layer chromatography (HPTLC), an improved technique for screening lichen substances.
231 citations
TL;DR: In this paper, 10 other fluoranthene metabolites were isolated from ethyl acetate extracts of the culture medium by thin-layer and high-performance liquid chromatographic methods on the basis of comparisons with authentic compounds by UV spectrophotometry and thin layer chromatography as well as gas chromatography-mass spectral and proton nuclear magnetic resonance spectral analyses.
Abstract: Mycobacterium sp strain PYR-1, previously shown to extensively mineralize high-molecular-weight polycyclic aromatic hydrocarbons in pure culture and in sediments, degrades fluoranthene to 9-fluorenone-1-carboxylic acid In this study, 10 other fluoranthene metabolites were isolated from ethyl acetate extracts of the culture medium by thin-layer and high-performance liquid chromatographic methods On the basis of comparisons with authentic compounds by UV spectrophotometry and thin-layer chromatography as well as gas chromatography-mass spectral and proton nuclear magnetic resonance spectral analyses, the metabolites were identified as 8-hydroxy-7-methoxyfluoranthene, 9-hydroxyfluorene, 9-fluorenone, 1-acenaphthenone, 9-hydroxy-1-fluorenecarboxylic acid, phthalic acid, 2-carboxybenzaldehyde, benzoic acid, phenylacetic acid, and adipic acid Authentic 9-hydroxyfluorene and 9-fluorenone were metabolized by Mycobacterium sp strain PYR-1 A pathway for the catabolism of fluoranthene by Mycobacterium sp strain PYR-1 is proposed
133 citations
TL;DR: Saccharomyces cerevisiae (dry baker's yeast) and Pseudomonas fluorescens were used to convert trans-ferulic acid into 4-hydroxy-3-methoxystyrene in 96 and 89% yields, respectively.
Abstract: Saccharomyces cerevisiae (dry baker9s yeast) and Pseudomonas fluorescens were used to convert trans-ferulic acid into 4-hydroxy-3-methoxystyrene in 96 and 89% yields, respectively. The metabolites were isolated by solid-phase extraction and analyzed by thin-layer chromatography and high-performance liquid chromatography. The identities of the metabolites were determined by 1H- and 13C-nuclear magnetic resonance spectroscopy and by mass spectrometry. The mechanism of the decarboxylation of ferulic acid was investigated by measuring the degree and position of deuterium incorporated into the styrene derivative from D2O by mass spectrometry and by both proton and deuterium nuclear magnetic resonance spectroscopies. Resting cells of baker9s yeast reduced ferulic acid to 4-hydroxy-3-methoxyphenylpropionic acid in 54% yield when incubations were under an argon atmosphere.
118 citations
TL;DR: In this paper, a simple and rapid procedure for the simultaneous determination of monoterpenes and diterpenoid resin acids of conifer stem oleoresin is described; it involves tissue extraction with methyl tert-butyl ether and methylation of the resin acids with CH2N2.
Abstract: A simple and rapid procedure for the simultaneous determination of monoterpenes and diterpenoid resin acids of conifer stem oleoresin is described; it involves tissue extraction with methyl tert-butyl ether and methylation of the resin acids with CH2N2. The resin acid methyl esters and the monoterpenes are then analysed in a single gas chromatographic step. Enantiomer composition of the major monoterpene constituents is determined, after preliminary purification by thin layer chromatography, by capillary gas chromatography on a cyclodextrin column. The method is applicable to conifer species of high resin content (Iodgepole pine) and low resin content (grand fir).
92 citations
TL;DR: A new strain of Bacillus subtilis C 126 was isolated from sugar cane fermentation and produced an antibiotic that inhibited the growth of Micrococcus flavus.
Abstract: A new strain ofBacillus subtilis C 126 was isolated from sugar cane fermentation and produced an antibiotic that inhibited the growth ofMicrococcus flavus. The production of the antibiotic in culture medium followed to extraction withn-butanol, thin layer chromatography, and microbiological tests indicated that a polypeptide antibiotic was produced. The fraction obtained by Sephadex G-25 column and analyzed by HPLC indicated that bacitracin complex was produced.
67 citations
Book•
01 Jan 1993
TL;DR: In this article, Betina et al. presented a technique for sample extraction and clean-up of mycotoxins using column and column-based methods, including column-column and mini-column methods.
Abstract: Part A Techniques: 1. Sampling, Sample Preparation, Extraction and Clean-up, V. Betina: Sampling and Sample Preparation Sample Extraction and Clean-up Illustrative Example. 2. Techniques of Thin Layer Chromatography, R.D. Coker et al: Clean-up Methods Normal Phase TLC Reverse-phase TLC (RPTLC) High Performance Thin Layer Chromatography (HPTLC) Preparative TLC Detection Quantitative and Semi-Quantitative Evaluation Illustrative example. 3. Techniques of Liquid Column Chromatography, P. Kuronen: Sample Pretreatment Column Chromatography Mini-Column Chromatography High-Performance Liquid Chromatography. 4. Techniques of Gas Chromatography, R.W. Beaver: Resolution in Gas Chromatography Extracolumn Resolution. 5. Emerging Techniques: Immunoaffinity Chromatography, A.A.G. Candlish and W. H. Stimson Immunoaffinity Chromatography Theory Practical Aspects and Instrumentation Sample Preparation Illustrative Examples. 6. Emerging Techniques - Enzyme-Linked lmmunosorbent Assay (ELISA) as Alternatives to Chromatographic Methods: C. M. Ward et al: Principles of ELISA Sample Preparation Instrumentation and Practice Illustrative Examples. Part B Applications: 7. Thin-Layer Chromatography of Mycotoxins, V. Betina: Aflatoxins Sterigmatocystin and Related Compounds Trichothecenes Small Lactones Macrocyclic Lactones Ochratoxins Rubratoxins Hydroxyanthraquinones Epipolythiopiperazine-3,6-diones Tremorgenic Mycotoxins Alternaria Toxins Citrinin G-Cyclopiazonic Acid PR Toxin and Roquefortine Xanthomegnin, Viomellein and Vioxanthin Naphtho-y-Pyrones Secalonic Acids TLC of Miscellaneous Toxins Multi-Mycotoxin TLC TLC in Chemotaxonomic Studies of Toxigenic Fungi. 8. Liquid Column Chromatography of Mycotoxins, J.C. Frisvad and U. Thrane: Column Chromatography Mini-Column Chromatography High Performance Liquid Chromatography Informative On-line Detection Methods. 9. Gas Chromatography of Mycotoxins, P.M. Scott: Trichothecenes Zearalenone Moniliformin Alternaria Toxins Slaframine and Swainsonine Patulin Penicillic Acid Sterigmatocystin Aflatoxins Ergot Alkaloids Miscellaneous Mycotoxins.
66 citations
TL;DR: It is shown here that the methylated 36-kDa polypeptide is a component of a cytosolic protein with a native molecular mass estimated at 178 kDa by gel filtration chromatography, providing evidence for a new type of reversible posttranslational modification reaction that may function to modulate the activities of its methyl-accepting substrates.
63 citations
TL;DR: In this paper, a procedure for the extraction and quantification of saponins is described, and the identification of the major components of the saponin mixture has been performed using thin layer chromatography and high performance liquid chromatography.
Abstract: The chemical characterization of the saponins and sapogenins isolated from roots and aerial parts of two alfalfa cultivars with differing saponin content is reported. A procedure for the extraction and quantification of saponins is described, and the identification of the major components of the saponin mixture has been performed using thin layer chromatography and high performance liquid chromatography. Characterization, using gas chromatography (GC) and GC/mass spectral analysis, of sapogenins released following acid hydrolysis allowed the identification of medicagenic acid, hederagenin, soyasapogenols B, C, D, E and F as the major compounds, together with oleanolic acid. Quantitative analysis of the sapogenins in aerial parts and roots of the two cultivars is reported and discussed.
59 citations
TL;DR: The procedure uses the original stage of separating phthalocyanine pigments and other “slightly soluble” organic pigments to examine colored components of printing and writing inks and other marking materials.
Abstract: A three-step thin-layer chromatographic procedure for examining colored components of printing and writing inks and other marking materials is described. The procedure uses the original stage of separating phthalocyanine pigments and other “slightly soluble” organic pigments. Experimental conditions are given.
47 citations
TL;DR: In this paper, the application of reversed-phase thin-layer chromatography (RP-TLC) for the chromatographic estimation of drug lipophilicity, some aspects of measuring true RM values [log (1/RF - 1)] are considered.
33 citations
01 Feb 1993-Zentralblatt Fur Bakteriologie-international Journal of Medical Microbiology Virology Parasitology and Infectious Diseases
TL;DR: Eleven different patterns based on number, type and Rf values of the detected lipid spots were identified and it was possible to relate these clinical isolates to mycobacterial groups defined by their mycolic acid profiles.
Abstract: The mycolic acid patterns of 75 strains of mycobacteria belonging to 46 different species were studied by thin-layer chromatography (TLC). Additionally, the mycolic acid pyrolytic cleavage products were determined by capillary gas-liquid chromatography (C-GLC). Eleven different patterns based on number, type and Rf values of the detected lipid spots were identified. The mycolic acid methyl ester profiles of clinical isolates were compared with those of reference strains. In this way, it was possible to relate these clinical isolates to mycobacterial groups defined by their mycolic acid profiles. The 11 patterns and the methods used are described in detail.
TL;DR: In this paper, the results for the thiamine, riboflavin, and niacin derivatives were determined using a commercially available fibre-optic-based instrument.
TL;DR: The utility of this method for the microsequencing of radiolabeled neutral glycans derived from two GPI glycolipids, using exoglycosidases and chemical treatments, is demonstrated, and is a simple and useful complement to the existing chromatographic techniques.
TL;DR: In this article, the retention and selectivity of flavonoids (baicalin, baicalein, wogonin, oroxylin A) inScutellariae radix have been studied by high-performance thin-layer chromatography on phenyldimethylethoxysilane-treated silica plates.
Abstract: The retention and selectivity of flavonoids (baicalin, baicalein, wogonin, oroxylin A) inScutellariae radix have been studies by high-performance thin-layer chromatography on phenyldimethylethoxysilane-treated silica plates. The silica plates treated with phenyl groups were used for physical and chemical analysis. From elemental carbon analysis, the maximum number of bonded phenyl surface groups per gram was calculated to be 0.467×1021 (Oginal silica plate: Merck Art. 15109, Silica gel 100 F254). With methanol-1/15 M phosphate buffer (pH 6.2) mixtures as mobile phase, baicalin, baicalein, wogonin, and oroxylin A inScutellariae radix were separated. It has been shown that phenyl-treated plates are more suitable for selective separation of baicalin, baicalein, wogonin, and oroxylin A than octadecyl-treated plates.
TL;DR: In this article, a simple and precise method using High-Performance liquid [HPLC] and High Performance Thin-Layer Chromatography [HPTLC] was developed for simultaneous determination of the frequently encountered cucurbitacins B (1), D (2), 3-epi-iso-cucurbitsacin D (3), E (4) and I (5) as well as cucurBITacin glycosides E (6) andI (7).
Abstract: A simple and precise method using High-Performance liquid [HPLC] and High-Performance Thin-Layer Chromatography [HPTLC] was developed for simultaneous determination of the frequently encountered cucurbitacins B (1), D (2), 3-epi-iso-cucurbitacin D (3), E (4) and I (5) as well as cucurbitacin glycosides E (6) and I (7). A reverse phase column [C-18] was used and elution achieved with acetonitrile-water [2:8, solvent A and 45:55, solvent B] with gradient elution analysis. Reverse-phase HPTLC plates were developed with methanol: water (7:3) and normal-phase plates were developed with toluene-ethylacetate (25:75). Developed plates were scanned with Thin-Layer Scanning Instrumentation. A clean-up procedure was perfected before sample loading to both the HPLC and HPTLC.
TL;DR: The microwave oven has been used to condition normal silica gel and argentation thin-layer chromatographic plates in a fraction of the time normally required, and the fatty acid compositions of intact tissues were determined using this technique.
Abstract: A technique is described for the methanolysis of fatty acids from acylglycerols with HCl/CH3OH or NaOH/CH3OH using a microwave oven. The esterification is rapid and complete and does not result in significant degradation of polyunsaturated fatty acids, even in the presence of oxygen. The fatty acid compositions of intact tissues were also determined using this technique. The microwave oven has also been used to condition normal silica gel and argentation thin-layer chromatographic plates in a fraction of the time normally required.
TL;DR: In this paper, the chiral selector β-cyclodextrin was used in the mobile phase along with either aqueous acetonitrile or methanol as an organic modifier.
TL;DR: The method described offers an easy to handle and successful preparative thin-layer chromatography strategy to obtain pure gangliosides in microgram and miligram quantities.
TL;DR: In this article, the lipophilicity (RM value) of 17 monoamine oxidase inhibitory drugs was determined by reversed phase thin-layer chromatography and the effect of various eluent additives such as acetic acid, sodiumacetate and sodium chloride on the retention was studied.
Abstract: The lipophilicity (RM value) of 17 monoamine oxidase inhibitory drugs was determined by reversed-phase thin-layer chromatography and the effect of various eluent additives such as acetic acid, sodiumacetate and sodium chloride on the retention was studied. Each drug exhibited regular retention behavior, their RM value linearly decreased with the increasing concentration of methanol in the eluent. Acetic acid decreased the retention, the effect was higher at lower acid concentrations which indicates that the phenomena is of saturation character. The effect of sodiumchloride and sodiumacetate was negligible. The lipophilicity and specific hydrophobic surface area values of the drugs were intercorrelated, however, their information content is different, therefore their simultaneous application in quantitative structure-activity relationship studies is recommended.
TL;DR: The simple and expedient alpha-tocopherol-directed autoxidative preparation of a series of monohydroxy derivatives of DHA to provide a relatively homogeneous hydroxylation along each of the double bonds of the fatty substrate is reported.
TL;DR: RP-HPLC with fluorescence detection proved to be the more sensitive method for detecting low levels of 4-hydroxycoumarins in blood serum, liver and ingesta, whereas TLC is usually sufficient for analysing baits.
Abstract: The detection of 4-hydroxycoumarin rodenticides in poisoned domestic animals requires a highly sensitive method as tissue and serum levels of anticoagulants may be very low owing to rapid elimination, metabolism or post-mortem degradation. Thin-layer chromatography (TLC) and reversed-phase high-performance liquid chromatography (RP-HPLC) with fluorescence detection were used to identify the anticoagulants in spiked tissues and in suspicious samples. The analysis of ten suspicious samples highlighted the limitations of both methods. Only the three samples of baits were found positive by TLC whereas one of the five anticoagulants was detected in eight samples by RP-HPLC with fluorescence detection. Therefore, RP-HPLC with fluorescence detection proved to be the more sensitive method for detecting low levels of 4-hydroxycoumarins in blood serum, liver and ingesta, whereas TLC is usually sufficient for analysing baits.
TL;DR: A procedure for the separation of positionally isomeric triacylglycerols by silver ion thin-layer chromatography at ambient temperature is described in this article, where low silver ion content in the silica gel layer, the mobile phase of chloroform-methanol and the development in open cylindrical tanks are found essential for the improved resolution of the SMS-SSM, SMM-MSM, SDS-SSD species.
Abstract: A procedure for the separation of positionally isomeric triacylglycerols by silver ion thin-layer chromatography at ambient temperature is described. The low silver ion content in the silica gel layer, the mobile phase of chloroform-methanol and the development in open cylindrical tanks are found essential for the improved resolution of the SMS-SSM, SMM-MSM, SDS-SSD species. Resolution of the DSD-DDS and DMD-DDM species is achieved also.
TL;DR: In this paper, a good separation of the components of various chemical classes of alkaloids is possible by overpressured thin-layer chromatography (OPTLC) on aluminium oxide plates with ethyl acetate alone as the mobile phase.
TL;DR: The enantiomeric resolution of (±)-hyoscyamine (atropine) and (±-colchicine was achieved on silica gel impregnated with an optically active acid, L-aspartic acid (.03%), as the chiral selector.
Abstract: The enantiomeric resolution of (±)-hyoscyamine (atropine) and (±)-colchicine was achieved on silica gel impregnated with an optically active acid, L-aspartic acid (.03%), as the chiral selector. The solvent system n-butanol chloroform acetic acid water (3∶6∶4∶1, v/v), was found to resolve (±) mixtures.
TL;DR: It is found that 0.2 M ammonium hydroxide worked well for the recovery, separation, and resolution of a wide array of adducts derived from highly lipophilic polycyclic aromatic hydrocarbons and aromatic amines.
TL;DR: A reproducible and validated assay based on solid phase extraction for the determination of the level of free iodide in [ 131 I]metaiodobenzylguanidine infusion fluids was proposed in this paper.
TL;DR: In this article, the authors extracted lipids from ground beef with methylene chloride/methanol (2:1) and separated them on a silicic acid column, into neutral and polar fractions, followed by methanol elution.
Abstract: Lipids were extracted from cooked ground beef with methylene chloride/methanol (2:1). The lipids were separated on a silicic acid column, into neutral and polar fractions by elution with methylene chloride, followed by methanol. These fractions were analyzed by Iatroscan thin-layer chromatography with flame-ionization detection instrumentation on Chromarods S-III (silica gelcoated quartz rods). Comparison of cooked beef stored for 0, 4 and 7 d at 4°C indicated that storage caused a decrease in total lipids, an increase in neutral lipids and a decrease in polar lipids, specifically in phosphatidylcholine. These changes in the lipid fraction were associated with meat flavor deterioration and an increase in lipid oxidation.
TL;DR: In this paper, an ion-pair and ion-suppression mode high performance liquid chromatography was conducted on the alkaloidal constituents of the roots of Artabotrys monteiroae.
Abstract: Ion-pair and ion-suppression mode high performance liquid chromatography was conducted on the alkaloidal constituents of the roots of Artabotrys monteiroae, an important medicinal plant in Kenya having analgesic and anti-inflammatory action. Use of sodium perchlorate as an ion-pair reagent led to excellent separation. In the ion-suppression system containing ammonium acetate, the separation was rather poor, but liquid chromatography-mass spectrometry was possible, which was not the case in the ion-pair system. Four aporphines, (-)-asimilobine, (+)-wilsonirine, (+)-norisoboldine and anonaine, and a benzylisoquinoline, (+)-reticuline, were identified after isolation by preparative thin layer chromatography.
TL;DR: In this article, a very sensitive and efficient high performance liquid chromtographic (HPLC) method for measuring 0.5-50 ng of free and acylated sterylglycosides (FSG and ASG) in oils in the form of their 1-anthroylnitrile derivatives has been developed.
Abstract: A very sensitive and efficient high performance liquid chromtographic (HPLC) method for measuring 0.5–50 ng of free and acylated sterylglycosides (FSG and ASG) in oils in the form of their 1-anthroylnitrile derivatives has been developed. Before to derivatization, the whole sterylglycosides were simply isolated with silica gel cartridge then fractionated via thin layer chromatography (TLC) into pure FSG and ASG. Derivatization was done on the FSG molecular species, therefore ASG was converted into FSG with mild alkaline hydrolysis. The derivatives separated by reversed phase mode were detected at 254 nm. Avenasterylglycoside can not be separated from isofucosterylglycoside and campesterylglycoside from stigmasterylglycoside. The method was successful with to different vegetable oils commercially extracted with hexane as well as those laboratory-extracted with a polar solvent mixture.