A semicrystalline inorganic ion-exchanger for thin-layer chromatographic separation of phenolic compounds

Summary The thin-layer chromatographic behaviour of 28 phenolic compounds was studied on semicrystalline stannic tungstate layers using various solvent systems of which formic acid and n-butanol-formic acid were found to be the most useful for the separation of these compounds. Dimethyl sulphoxide was found to act as a self detector for a number of phenols. An interesting feature of the study of phenols using stannic tungstate is the novel separation of different isomeric compounds. A number of binary, ternary and quarternary separations of bioanalytical and immunophysiological importance have been achieved.     

Thin-layer chromatographic separation and analysis of polynuclear aza heterocyclic compounds

Many thin-layer Chromatographic systems can be used for the general separation of aza heterocyclic compounds from polynuclear aromatic hydrocarbons. Several can be used for the separation of the aza compounds from each other. With alumina as the adsorbent the sterically hindered aza heterocyclic compounds can be readily separated from the non-hindered aza compounds.The use of the trifluoroacetic acid spot test on the thin-layer plate is discussed. Spectral data for the aza compounds are presented and discussed.     

A thin-layer chromatographic procedure for estimating traces of copper in edible fats

Summary To carry out estimations as stated in the title, the sample matrix was first destroyed by an improved incineration procedure. Very small quantities of copper (not exceeding, however, 0.03 μg/cm in the chromatogram) were estimated by measurement of fluorescence after spraying with an ammonium phosphate reagent. Larger quantities (up to 0.3 μg/cm) were estimated on the basis of copper-induced quenching of fluorescence produced by spraying the developed chromatograms with glucose. In these experiments the metal is located as non-fluorescent areas on a yellowish-green fluorescent background.     

A quantitativein situ fluorimetric study of acridine and 5,6-benzoquinoline after thin-layer chromatographic separation from similar air pollutants

Summary Acridine and 5,6-benzoquinoline have been studied extensively byin situ fluorimetry in an attempt to evaluate the potential of this method for quantization of mixtures of polynuclear aza heterocyclic hydrocarbons in polluted air samples. The stabilities of naturally fluorescing acridine and 5,6-benzoquinoline were found to be sufficient for quantitative work if processed in the dark. Between 4 and 6% rel. S. D. and 2 and 3% rel. S. D. respectively are reported for these two compounds after onedimensional chromatography. Improvements of 3 to 5% rel. S. D. were achieved with the use of an internal standard in conjunction with twodimensional chromatography. Spraying with trifluoroacetic acid to render nonfluorescent aza arenes such as phenazine fluorescent did not produce a sufficiently stable derivative to permit quantitative analysis. Visual and instrumental detection limits of 0.005g/spot are reported for this method, with linear calibration curves of fluorescenceversus concentration extending up to 0.5g/spot. The optimum range of analysis is reported to be 0.1 to 1g/spot.

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Zusammenfassung Um die Eignung der Fluoreszenzmessung zur Analyse von Gemischen mehrkerniger Azaverbindungen in Luftproben zu prüfen, wurden Acridin und 5,6-Benzochinolin eingehend untersucht. Die Stabilität dieser Substanzen ist hinreichend für eine quantitative Arbeit, wenn sie unter Lichtabschluß durchgeführt wird. 4 bis 6 Rel.-% bzw. 2 bis 3 Rel.-% Standardabweichung wurden bei eindimensionaler Chromatographie der beiden Verbindungen gefunden. Durch Verwendung eines inneren Standards und durch zweidimensionale Chromatographie wurden diese. Werte um 3 bis 5 Rel.-% verbessert. Sprühen mit Trifluoressigsäure, um nichtfluoreszierende Azaverbindungen wie Phenazin zur Fluoreszenz zu bringen, führte nicht zu genügend stabilen Derivaten, um eine quantitative Analyse zu ermöglichen. Nachweisgrenzen von 0,005g je Fleck sind mit der angegebenen Methode erreichbar. Die Eichkurven zeigen die lineare Abhängigkeit der Fluoreszenz von der Konzentration bis zu 0,5g je Fleck. Das bestgeeignete Bereich liegt zwischen 0,1 und 1g je Fleck.

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On study leave from Robapharm Ltd., Basle, Switzerland.     

Improved quantitative thin-layer chromatographic method for the separation of cobalamin derivatives

Summary A new quantitative thin-layer chromatographic method was developed for the separation and determination of cobalamin derivatives. A mixture of acetone, acetonitrile, isopropanol, diethylamine and aqueous ammonium hydroxide as the eluent and precoated Kieselgel 60 chromatoplate as the TLC plate was used. The evaluation of the separated spots was carried out by densitometry. The method can be used for the determination of cyanocobalamin in fermentatic mixture without any cleaning or concentration procedure as well as for the purity test of cyanocobalamin and hydroxocobalamin.     

Reverse phase thin-layer chromatographic separation of bromodiphenhydramine and diphenhydramine.

A thin-layer chromatographic system is described for the separation of diphenhydramine and bromodiphenhydramine which is based on a reverse phase paper chromatographic system developed by J. Vecerková (2,3) in 1962. Chromatographic systems for this separation described in the literature and several systems attempted in this laboratory using normal chromatography have not proven successful. The method using reverse phase thin-layer chromatography involves a stationary phase of mineral oil on silica gel G and a mobile phase of ethanol:water:ammonium hydroxide, 28% NH3, (55:43:2). A 10-cm length of run requires about three hours and provides an excellent separation of the two compounds for identification-differentiation purposes.