[Sintered thin-layer chromatography. XII. Thin-layer chromatography on porous metal oxides sintered plates (author's transl)].
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Adsorption↗
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Quantitative thin-layer chromatography: thin-film fluorescence scanning analysis of adriamycin and metabolites in tissue.
A rapid, non-hydrolytic thin-film fluorescence scanning method is described for the quantitation of adriamycin and metabolites in tissues. Adriamycin, with daunomycin added as the internal standard, was extracted from tissue homogenate which contained 500 micrograms of oxalic acid, with ice-cold 0.5 N hydrochloric acid--85% isopropanol, separated by thin-layer chromatography, and quantitated in situ via a fluorescence scanning technique. This method has a sensitivity to 0.05 microgram per gram of tissue.
Animals↗
Improvements in the thin-layer chromatography of natural products. I. Thin-layer chromatography of the aflatoxins.
During the period which has elapsed since the aflatoxins were first isolated, one of the main problems has been the separation of the individual aflatoxins in pure form from aflatoxin-containing extracts. This separation has been best effected by thin-layer chromatography, and in this paper we describe how some of the difficulties may be overcome by using an appropriate combination of solvent system and silica gel preparation. For the examination of aflatoxin-containing extracts from the mycelia of Aspergillus flavus moulds, an initial freeze-drying step has been found to improve appreciably the quality of the chromatograms obtained.
Acetates↗
The determination of paraquat using thin-layer chromatography.
A thin-layer chromatographic method for the detection and determination of Paraquat in biological materials is presented. Paraquat was concentrated efficiently with the ion-exchange resin Dowex 50W-4 using a batch operation. Of the 16 solvent systems used the best results were obtained on silica gel G plates with methanol : 6N hydrochloric acid (20 : 30) or methanol : 6N sulfuric acid (20 : 30); and on cellulose plates with methanol : 6N hydrochloric acid (35 : 15) or methanol : 6N sulfuric acid (40 : 10). Also described is a microplate method for the thin-layer chromatography of Paraquat.
Animals↗
Class separation of bile lipids by thin-layer chromatography.
A thin-layer chromatography technique is described that permits separation of each class of bile lipid, such as cholesterol, free (unconjugated) bile acids, glycine- and taurine-conjugated bile acids and phospholipids, in a single run. The use of silica gel G-aluminium pre-coated sheets facilitates further processing, such as the extraction in situ of each class of separated bile lipids for determination by conventional methods.
Bile↗
Resolution of saturated and unsaturated 5 beta-cholanoic acids by gas-liquid and thin-layer chromatography.
The thin-layer and gas-liquid chromatographic properties of the methyl ester acetates were determined for a series of 20 monounsaturated 5 beta-cholanoic acids representing the simple chemical and enzymic dehydration products of the common bile acids. The unsaturated acids were generally indistinguishable from their saturated analogues by thin-layer chromatography on plain silica gel, but resolution was achieved on silica gel impregnated with silver nitrate for compounds having sterically exposed double bonds. The gas-liquid chromatographic behaviour of the unsaturated bile acids on the OV-225, SE-30, and Poly-S-179 liquid phases was closely similar to that observed for the saturated bile acids. The 5 beta-cholenoic acids obeyed the general rules of chromatographic mobility based on the overall shape of the molecule and the number and configuration of functional groups, with a constant retention factor attributable to the olefinic bond. The structural information provided by the chromatographic behaviour of the standard unsaturated bile acids allows a distinction to be made among most of the isomeric 5 beta-cholenoates. A complete identification of all isomeric olefins is possible when chromatographic and mass spectrometric data are combined.
Bile Acids and Salts↗
Isotopic fractionation in thin-layer chromatography.
The thin-layer chromatography of imipramine on silica gel plates was studied in fifteen solvent systems. The mobility of imipramine labeled with deuterium in the methyl groups of the dimethylaminopropyl side chain differs markedly from that of unlabeled imipramine. Partial or complete separations between unlabeled and deuterated imipramine were observed in all basic and neutral solvent systems investigated, but not in weakly acidic solvents. Isotopic fractionations of imipramine were also found on alumina thin-layer plates, but were not detected in cellulose chromatography. In all thin-layer isotopic separations, the unlabeled compound migrates more rapidly than the deuterated molecule. These results can be explained by a stronger basicity of deuterated imipramine relative to its unlabeled counterpart.
Chromatography, Thin Layer↗
Determination of amitriptyline and nortriptyline in human plasma by quantitative thin-layer chromatography.
A thin-layer chromatographic method for simultaneous determination of amitriptyline (AT) and nortriptyline (NT) in human plasma is described. Both substances are extracted from biological material by means of a single extraction. The extract is evaporated until dry and the residue quantitatively applied to a silica gel thin-layer plate. AT and NT are separated from interfering plasma components by chromatography. The spots are visualized by nitration, reduction and coupling with N-(1-naphtyl)ethylenediamine on the plate. The intensity of the azo-dyes formed can be measured densitometrically. Using 1 ml of plasma, the sensitivity limit was 0.5 ng/ml for both substances. About 10--15 plasma samples can be analysed per day. The method is applicable to pharmacokinetic studies after a single oral dose of 25 mg AT as hydrochloride in man.
Amitriptyline↗
Detection of sodium alkanesulphonates and alkylbenzenesulphonates by polyamide thin-layer chromatography.
A thin-layer chromatographic method was investigated in which two series of sodium alkanesulphonates (C4-C18) and alkylbenzenesulphonates (C0-C14) were separated. All of the compounds tested were clearly separated on polyamide layers with aqueous ammonia-pyridine and aqueous ammonia-pyridine-methanol systems and detected with high sensitivity by spraying with a pynacryptol yellow reagent and then observing under UV light (253.6nm).
Alkanesulfonates↗
Separation of nebramycin components by thin-layer chromatography.
A thin-layer chromatographic method has been developed for the detection of major nebramycin components, for the separation of tobramycin from other components and for studying the hydrolysis of carbamoyl derivatives and procedures for isolation and purification. A sensitive method has also been established for the detection of kanamycin B in tobramycin and for the assay of apramycin in kanamycin B.
Anti-Bacterial Agents↗
Separation of androsterone from epiandrosterone, and dehydroepiandrosterone from its 3-hydroxy epimer by thin-layer chromatography.
The application of thin-layer chromatography to the separation of 13 steroids, including androstanes, 4-androstenes and 5-androstenes, using silica gel and 1,2-propanediol-impregnated cellulose is described. After group-wise separation of various C19 steroids on silica gel, the 3-hydroxy epimers of 5alpha-androstanes and 5-androstenes can be separated by thin-layer chromatography on impregnated cellulose plates. The chromatographic procedure is rapid and makes the prior formation of steroid derivatives unnecessary.
Androsterone↗
Sebum composition: a comparison of thin-layer chromatography and infrared reflectance spectroscopy.
Thin-layer chromatography and infrared reflectance spectroscopy were compared as methods for measuring sebum composition. Solutions of varying known concentrations of free fatty acids and triglycerides were analyzed by both methods. Skin surface lipid samples were similarly analyzed. Infrared spectroscopy produced more variable data than thin-layer chromatography with photodensitometry. This was particularly true at low concentrations of free fatty acids. It is concluded that thin-layer chromatography with photodensitometry is a more accurate method for the measurement of sebum composition.
Chromatography, Thin Layer↗
Isolation and characterization of pteridines from heads of Drosophila melanogaster by a modified thin-layer chromatography procedure.
An improved thin-layer chromatography technique is described for the separation of fluorescent compounds found in extracts of heads of Drosophila melanogaster. Eighteen to twenty fluorescent spots are resolved, two of which are xanthurenic acid and 3-hydroxykynurenine, and the remaining spots are presumably pteridines. Of these, nine have been identified and quantitated directly on the chromatograms with a fluorometer. One of the spots present on the chromatogram apparently has not been described previous to this work. Characteristics of this substance, termed "quench spot," are presented, several of which indicate that it may be a pteridine or pteridine derivative.
Animals↗
Determination of drugs in plasma by high-performance thin-layer chromatography.
High-performance thin-layer chromatography was used to determine chlorpromazine, amitriptyline, nortriptyline, imipramine, desipramine, phenobarbital, and phenytoin in plasma, to demonstrate the utility of this technique for routine analysis. We quantitated the separated components by use of ultraviolet reflectance spectrometry with detection limits as low as 1 microgram/liter. Regressions of psychoactive agents extracted from plasma were linear over the range of 0 to 300 microgram/liter. The anti-convulsant drugs, phenobarbital and phenytoin, were determined over a range of 0 to 50 mg/liter. Analyses were rapid, reproducible, and well-suited to large-scale programs. Separated components also can be identified in situ by ultraviolet spectrophotometry.
Amitriptyline↗
A simple screening method for plasma lipids by thin-layer chromatography with flame ionization detection.
Thin-layer chromatography was carried out on glass rods coated with Silica gel (chromarod) and the fractions were detected with a flame ionization detector (FID). This system was applied to the fractionation and screening of plasma lipids. As the relative response of the flame ionization detector depends on the nature of the lipids, correction factors had to be introduced. These correction factors were derived from comparison of the results of the thin-layer chromatography with flame ionization detection with those obtained by conventional chemical analysis of the same sample. The coefficients of variation of the lipid profiles were comparable for both techniques. The absolute lipid concentration for the various fractions obtained by combination of the concentration of the total lipids with the relative lipid profile, correlate very well with the values obtained by conventional chemical analysis of the various lipids.
Cholesterol↗
Thin-layer chromatography of chlorinated catechols.
The thin-layer chromatography of catechol and six chlorinated catechols has been studied on five adsorbents. Acetic acid in the developing solvent was essential for the production of sharp zones. The best separation of the individual compounds occurred on alumina, whereas silica gel appeared to be good for group separation (clean-up) from other compounds.
Catechols↗
Drug screening by enzyme immunoassay (EMIT) and thin-layer chromatography (Drug Skreen).
Urine samples (n = 300) were examined for drugs by thin-layer chromatography ("Drug Skreen", Brinkmann Corp.) and by the "Enzyme Multiplied Immunoassay Technique" ("Emit", Syav Corp.). The results of both methods were compared for the detection of opiates, barbiturates and amphetamines. In more than 90% of the determinations identical results were obtained with both methods. About 10% of the results of the Emit barbiturate assay differed from those of thin-layer chromatography and therefore had to be further investigated by gas liquid chromatography. It could be demonstrated that the barbiturate determination by the Emit system correlated better with the results of gas liquid chromatography. From the results of this study it is suggested that thin-layer chromatography is used as a screening test, and to confirm positive results with other methods such as Emit. If the abuse of barbiturates or opiates is suspected the corresponding Emit test should also be performed, even in cases of a negative thin-layer chromatography screening. Confirmation with a third method such as gas liquid chromatography is necessary, if thin-layer chromatography and Emit lead to divergent results.
Amphetamines↗
Assay of human plasma for nortriptyline by radioacetylation and thin-layer chromatography.
A highly specific and sensitive thin-layer chromatographic method for determining nortriptyline levels in plasma is presented. The procedure involves extracting nortriptyline, acetylating it with radioactive acetic anhydride, resolving acetylnortriptyline by thin-layer chromatography, and measuring its radioactivity.
Acetylation↗