A Spray Reagent for Identification of Amino Acids on Thin-Layer Chromatography Plates

JPC – Journal of Planar Chromatography – Modern TLC -     

An Improved Copper Reagent for Quantitative Densitometric Thin-Layer Chromatography of Lipids

Abstract

Eleven cupric compounds were screened to determine whether a different cupric anion might give greater and more uniform charring responses with lipid classes on TLC plates than cupric acetate. A procedure was developed which used 10% CuSO₄ in 8% H₃PO₄ as a charring reagent. Improved reproducibility of charring was obtained by temperature-programmed heating of the thin layer plates from 30 to 180°C at 10 degrees per minute in the oven of a commercial gas-liquid chromatograph.     

A New Reagent for Identification of Amino Acids on Thin-Layer Chromatography Plates

JPC – Journal of Planar Chromatography – Modern TLC -     

Congo Red as a Spray Reagent for the Visualization of Dithiocarbamate Fungicides Separated On Thin-Layer Chromatograms

Abstract

Congo red as a single spray reagent locates and identifies dithiocarbamate fungicides after their separation on thin-layer chromatograms. The chromatogram is sprayed with Congo red which stains the entire chromatogram red. While still wet the chromatogram is exposed to bromine vapor in a glass tank. Dithiocarbamates appear as blue spots against a bleached background. A second spray with the reagent after the dissipation of the bromine intensifies the blue spots and turns the background red. The blue spots are very well defined and stable if protected from light. The procedure is rapid and requires no heating.     

A New Chromogenic Spray Reagent for the Detection and Identification of 2,4-Dichlorophenol,an Intermediate of 2,4-D Herbicide in Biological Material by High-Performance Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - 2,4-Dichlorophenoxyacetic acid (2,4-D) is a phenoxy group of herbicide used worldwide. As it is extensively used, it has...     

Influence of Fermentation Beetroot Juice Process on the Physico-Chemical Properties of Spray Dried Powder

Picking vegetables is, along with salting and drying, one of the oldest ways to preserve food in the world. This is the process of decomposition of simple sugars into lactic acid with the participation of lactic bacteria. The aim of the study was to obtain powders from fermented red beet juice with the highest possible amount of lactic acid bacteria (LAB) and active ingredients. For the analysis, juices were squeezed from the vegetables and two types of fermentation were used: a spontaneous fermentation and a dedicated one. After inoculation, samples were taken for analysis on a daily basis. Extract, pH, total acidity, pigments, and color were measured. In addition, microbiological tests were also carried out. The juices from the fifth day of fermentation was also spray dried, to obtain fermented beetroot powder. Juices from 3–5th day were characterized by a high content of LAB and betanin, had also a low pH, which proves that the lactic fermentation is working properly. The exception was the juice from spontaneous fermentation. According to the observations, the fermentation process did not run properly, and further analysis is needed. The powders were stable; however, results obtained from the pigment content and the LAB content are not satisfactory and require further analysis.     

Two-Dimensional Thin-Layer Chromatography of Polyaromatic Hydrocarbons Measured by Absorption,Fluorescence, and Chemiluminescence

JPC – Journal of Planar Chromatography – Modern TLC - A 2D-separation of 16 polyaromatic hydrocarbons (PAHs) according to the Environmental Protecting Agency (EPA) standard was...     

新型荧光试剂柱前衍生化高效液相色谱荧光检测法测定醇类化合物

采用新型的紫外、荧光衍生试剂咔唑－9－乙基氯甲酸酯，对15种脂肪醇柱前衍生的反应条件，包括反应温度、催化剂的选择、衍生化时间等，进行了考察。结果表明：催化剂选用吡啶，反应温度80℃，时间15min，衍生化具有最大且恒定的检测响应。利用高效液相色谱对衍生产物进行分析，同时对衍生物的分离进行了优化选择，达到了较好的基线分离。检测限为13.3-93.5nmol/L。     

The N-Chamber of the New Type for Rapid Thin-Layer Chromatography

The N-chamber, the most often in the method of thin-layer chromatography (TLC) for the separation, is used with the previous process of equilibrium saturation of the TLC plate with the mobile phase (MP) vapors, what, unfortunately, requires about 1 h. For the acceleration of the processes of saturation of the analytical plate with the vapors of the mobile phase, the use of a specially developed N-chamber of the new type containing a specific cassette holder has been proposed. In this cassette holder, a feeding plate (that is a TLC plate, previously wetted by MP) was additionally placed parallel to the analytical plate at a very small distance (0.2–1.0 mm). In these conditions, the process of saturation of the analytical plate with the MP vapors is accelerated substantially, and it passes with the improved repeatability. The new approach permitted to substantially (up to 2 times) decrease the time necessary for the TLC plate development in the N-chamber.     

Thin-Layer Chromatography for Selective Detection of Methomyl in Forensic Casework

JPC – Journal of Planar Chromatography – Modern TLC -     

Optimization of Solvent Composition for High Performance Thin-Layer Chromatography

Abstract

The methodology of mixture experiments has been applied to optimize the multicomponent solvent composition for high performance thin-layer chromatography (HPTLC). In this study, a mixture of five solvents for the mobile phase was maximized for the separation of twelve structurally related B(a)P metabolites on normal phase HPTLC plates. Volume fractions (rather than absolute quantities) of the mobile phase solvents were constrained by upper bounds by considering solvent strength. These restrictions defined an experimental region that is an irregular polyhedron formed from a truncated 4-dimensional simplex. The optimization of the expected separation response over the experimental region was based on a second-order Scheffé polynomial estimated from twenty-five experimental runs. Six functions for measuring separation based on R_f values were evaluated. A new response function is proposed that overcomes the difficulties of previously published criteria.     

A New Instrument for Automated Multiple Development in Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - A new AMD instrument made in our laboratory is described in this paper. The main advantages of the instrument are very low cost...     

Computer-Assisted Prediction of Retention in Multiple-Development Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - Retention of DNP derivatives of amino acids has been described by equations based on polynomial and Snyder—Soczewiński...     

The Use of Thin-Layer Chromatography in Experimental Xenobiology

Abstract

Studies of the metabolism and disposition of most drugs or other xenobiotics share one common feature: the need for an analytical method to measure the xenobiotic and/or its biotransformation products in biosamples. Although chromatographic methods such as GC and HPLC are important and preferred by some laboratories, initial investigations of new xenobiotic entities are often conducted using radiolabeled compounds, and, in such instances, TLC assay methods are frequently selected.

TLC is utilized in xenobiotic metabolism and disposition studies to evaluate the radiochemical purity of labeled xenobiotics, the extent of metabolism, the profile of metabolites in blood and excreta, the concentrations of the xenobiotic and specific metabolites in blood and other biosamples, the stability of the xenobiotic and its metabolites in biosamples, and the relative behavior of metabolites and reference compounds. Preparative TLC is frequently used to isolate specific metabolites. Thin-layer radiochromatography (TLRC) has been utilized to study the pharma-cokinetics of drugs and other xenobiotics in man and in animals. Especially where radiolabeled compounds are used, TLC provides an attractive chromatographic alternative to GC and HPLC in research in experimental xenobiology.     

The Role of Spacers in Displacement Thin-Layer Chromatography

Abstract

Displacement chromatography generates highly concentrated bands which migrate closely to each other along the stationary phase bed.

Spacer-displacement thin-layer chromatography is a planar method improving the observable resolution by inserting odd compounds (spacers) among the members of displacement train to be separated.

Substances were chromatographed by displacement mode of development using silica plates, chloroform carrier and triethanolamine displacer.

Resolution formula valid for elution chromatography has been adapted to the displacement type of developments. Explanation for the numerical value of required separation is given for various cases of displacement thin-layer chromatography.

Equations are suggested in order to calculate yield, loss and efficiency of displacement chromatography.     

Investigation of the Flavonoids in Croatian Propolis by Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - Flavonoids and phenolic acids with a variety of biological activity are considered to be the main compounds in propolis–a...     

Mixed Supports in the Reversed-Phase Thin-Layer Chromatography of Amino Acids

Abstract

Lipophilicity of amino acids was determined by reversed-phase thin-layer chromatography using silica, aluminium oxide, cellulose, diatomaceous earth and their mixtures as supports with water as eluent.

To compare the retention behaviour of supports principal component analysis /PCA/ was applied. The potency order and the selectivity of support mixtures was calculated by the spectral map technique. Linear and logarithmic correlations were calculated between the first PCA loadings and the potency values as dependent variables and the composition of supports as independent variables.

The first eigenvalue explained more than 90% of the total variance that is only one hidden factor influenced decisively the retention. On the basis of structural differences the retention strength of amino acids on support mixtures can not be explained adequately. The first principal component responsible for the 90% of change in the retention of amino acids is related to the logarithm of support composition that is the sorbents retain their original adsorptive character also after impregnation.     

N-二氯乙酰基噁唑烷合成反应的薄层色谱法研究

用薄层色谱法监测了用二氯乙酰氯、醇胺和酮合成的除草剂的安全剂N 二氯乙酰基 口恶唑烷的反应过程。方法操作简便、快速、准确。     

A New Way of Using Chemiluminescence in Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC -     

Densitometric Thin-Layer Chromatography of Protease Inhibitors in Pharmaceutical Preparations

JPC – Journal of Planar Chromatography – Modern TLC -