Triangular Thin-Layer Chromatography

Abstract

This study illustrates the use of triangular plates in thin-layer chromatographic separations. A comparison between triangular, conventional and circular thin-layer chromatography clearly indicates the superiority of triangular plates in terms of sensitivity, detection limits and savings in plates and solvent.     

Two-Phase Thin-Layer Chromatography

Abstract

Thin layer chromatography (TLC) is normally carried out on single-phase (adsorbent) plates. However, it may be necessary to use nore than one adsorbent to achieve the separation of complex mixtures. Literature reports indicate that the use of mixed phases in TLC is not very common, possibly because the plates are difficult to prepare and precoated single-phase plates of different absorbents are readily available (silica gel, reversed phase, cellulose. alumina, etc.).     

Surfactants in Thin-Layer Chromatography

Data reported in the literature on the use of surfactants as modifiers of mobile and stationary phases in thin-layer chromatography are analyzed. The features of micellar and ion-pair versions of thin-layer chromatography and the dynamic and static modifications of stationary phases with surfactants are considered.     

Circular-Development with Overpressured Thin-Layer Chromatography

Abstract

A novel type modification of circular thin-layer chromatography has been developed, in which the layer is tightly covered by a membrane, eliminating the vapour phase over the sorbent layer. The developing solvent is pumped through the apparatus.     

International Symposium on Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC -     

On-Plate Electrochemical Detection for Thin-Layer Chromatography

Abstract

Voltammetric electrochemical detection (ECD) coupled with thin-layer chromatography (TLC) was demonstrated for the quantification of trace organic compounds directly on a TLC plate. the electrochemical detection solvent was a thin layer of aqueous potassium chloride. For undeveloped plates, detection limits for p-anisidine and p-phenetidine were 10 ng and 13 ng, respectively. Linearity was demonstrated over nearly 2 orders of magnitude. After development, detection limits increased by approximately a factor of ten. Advantages of this method over other quantitative TLC methods include sensitivity, speed, simplicity, and cost. in addition, this method is selective for electrochemically active compounds. Major sources of experimental error include spot size reproducibility, working electrode placement, and supporting electrolyte film thickness.     

Overpressured Thin-Layer Chromatography and Its Applications

Abstract

In recent years, a rapid progress can be observed both in column and planar liquid chromatographic techniques. In the field of liquid column chromatography the most spectaular achievement was the development of high-performance liquid chromatographic/HPLC/ systems by means of several special instruments and sorbents/1, 2/. As regards planar techniques, the most significant break-through is the development of highperformance thin-layer chromatography/HPTLC//3/ based on the application of fine-particle sorbents. Both techniques proved to be very useful in many fields of chemical analysis, although the use of the latter is more restricted, mainly to micro chromatographic studies.     

Analysis of PCB's by Thin-Layer Chromatography

Abstract

A screening thin layer chromatography (TLC) technique has been developed that can be done in the field. Quantitative analysis by TLC densitometry can be done in a laboratory (or field van). A densitometer is needed for quantitative work by TLC. An Apple computer may be added to use as a computational device. Semi-quantitative results may be obtained by visual comparisons. Confirmations may be made by silver halide visualization on TLC. Dehalogenation with sodium biphenyl, chlorination with antimony pentachloride, or mass spectral confirmation may be used. Quantitative analysis is possible of the derivatized positive samples.     

Salting-Out Thin-Layer Chromatography of Several Myorelaxants

JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of five myorelaxant drugs has been studied under the conditions used for salting-out thin-layer...     

New Evaluation Algorithm in Diode-Array Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - In-situ densitometry for qualitative or quantitative purposes is a key step in thin-layer chromatography (TLC). It is a simple...     

Triterpene Glycosides Analyzed by Two-Dimensional Thin-Layer Chromatography

Two-dimensional TLC with judiciously chosen solvent systems that differ in pH values is proposed for identification of triterpene glycosides in plant extracts (mono- and bisdesmosidic, acidic, sulfated, acylated)     

Recent Developments in Thin-Layer Chromatography - II

Abstract

This review updates the one we did 4 years ago. The emphasis is on technique rather than application. Recent advances in adsorbents, plate shape, developing chambers, gradient elution and quantification methods are reviewed and commented on. Theoretical studies of the basic aspects of TLC processes are also reviewed.     

大豆磷脂组成的薄层色谱分析

采用国产硅胶板和二次展开的薄层色谱法，对具有重要的生物功能的大豆磷脂组成进行了分析，获得了大豆磷脂中１１个重要组分的定性结果。用已知样品量的薄层光密度扫描方法建立了卵磷脂定量方法，线性关系良好，并用于实际样品的测定，获得了满意结果。     

Thin-Layer Chromatography of Phenolic Acids on Aminopropylsilica

JPC – Journal of Planar Chromatography – Modern TLC - The possibility of using aminopropylsilica TLC plates for determination of phenolic acids has been investigated. Eighteen phenolic...     

Anodic Sampling of Titanium by Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - Titanium as the pure metal or as commercial titanium alloys has been widely used in dentistry. To determine the composition of...     

蔗糖酯的薄层分析

 以硅胶G板为固定相、甲苯 乙酸乙酯 甲醇 水 (体积比为 1 0∶5∶4 5∶0 2 )为流动相 ,研究建立了蔗糖酯薄层分析方法。在蔗糖酯上行展开后 ,用脲 磷酸 水饱和正丁醇溶液显色 ,斑点呈蓝色 ,蔗糖单酯的Rf 值为 0 1 6 ,多酯的Rf 值为 0 38～ 0 93。在 70℃显色 2 0min的最佳条件下 ,蔗糖单酯的检测量为 2 5 μg～ 2 50 μg时 ,其斑点面积与其检测量有良好的线性关系。用归一法和外标法对该分析方法的准确度进行考察和认证 ,两种方法对已知单酯含量的S 1 570样品测定结果的t 检验结果分别为 |t| =0 62 7(<2 571 )和 |t|=1 1 2 3(<2 571 ) 。     

薄层色谱法分离二元羧酸

利用薄层色谱法分离了二元羧酸,结果令人满意。     

Reversed-Phase Thin-Layer Chromatography of Some Foodstuff Dyes

JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of nine frequently used water-soluble food dyes has been studied by TLC on RP-18 silica gel....     

Ion Exchange Application of Overpressured Thin-Layer Chromatography

Abstract

The application of overpressured thin-layer chromatography introduced into the field of ion exchange chromatography. The basic differences between overpressured thin-layer chromatography and classical thin-layer chromatography are discussed including the distinction between the separations performed on thin-layer plates containing silica gel and a mixture of ion exchanger material and silica gel. The basic increase of flow velocity of solvent front with the aid of a pressurized ultra-micro chamber and the effect of flow velocity on the height equivalent of the theoretical plates are also presented. For basic amino acids, the flow velocity vs plate height curves show optima at a moderately high rate of development.