Applicability of a Monolithic Column for Separation of Isoquinoline Alkalodis from Chelidonium majus Extract

Isoquinoline alkaloids are the main group of secondary metabolites present in Chelidonium majus extracts, and they are still the object of interest of many researchers. Therefore, the development of methods for the investigation and separation of the alkaloids is still an important task. In this work, the application potential of a silica-based monolithic column for the separation of alkaloids was assessed. The influence of the organic modifier, temperature, salt concentration, and pH of the eluent on basic chromatographic parameters such as retention, resolution between neighboring peaks, chromatographic plate numbers, and peak asymmetry were investigated. Based on the obtained results, a gradient elution program was developed and used to separate and quantitatively determine the main alkaloids in a Chelidonium majus root extract.

A Rapid Thin Layer Chromatographic Method for Simultaneous Screening of Albendazole and Ivermectin in Formulations Prescribed for Human or Veterinary Use

An easy and selective thin layer chromatographic method has been developed and experimentally validated for the simultaneous screening of most commonly used anthelmintic drugs i.e. albendazole and ivermectin. Separation of these compounds was attained on silica gel 60 F254 pre-coated thin layer chromatographic plate using an optimized mobile phase of diisopropyl ether:ethyl acetate:glacial acetic acid in the ratio of 7:3:0.1 (v/v), respectively at pH 3.5. The calculated Rf values for albendazole and ivermectin were 0.65 and 0.38, respectively and the LOD was found to be 25 μg/ml and 30 μg/ml for albendazole and ivermectin, respectively. The developed method is selective, sensitive, robust, cost effective, eco-friendly, rapid as well as easy to perform. The developed method was successfully applied for the analysis of albendazole and ivermectin in pharmaceutical preparations marketed as oral suspensions, powder, tablets and injectable of the single or combined dosage forms for human as well as veterinary use. It could also be applied for the simultaneous analysis of both the compounds in other samples.

Acquisition of Images and Parameter Calculations for the Automatic Identification of Molecules in a Thin-film Extract Combined with Laser

This paper presents the automation of the thin-layer chromatography technique whose separation and identification of molecules present in a mixture are currently done manually and laboriously [1]. We have therefore found an interest in automating this technique. In this part, the method implemented comprises 2 steps. First we proceeded to the segmentation of the spots obtained on the chromatographic plate. We then developed a program to identify families of molecules such as coumarins, terpenes, tannins, flavonoids, polyphenols, etc. by calculating segmentation parameters such as standard deviation, entropy, average pixel intensity from an algorithm on the matlab software. Finally our results have been compared to the results obtained by the traditional identification technique in laboratories. Some similarity between the two results obtained shows the reliability and the robustness of our technique.

SIMULATION OF TWO-DIMENSIONAL ONE-PHASE TRACER FLOW WITH THE USE OF CHROMATOGRAPHIC PLATE THEORY

Generalization of chromatographic plate theory in case of two-dimensional non-sorbing tracer flow in a homogeneous porous media of uniform thickness with equal debit injection and producing wells are considered. It is shown that in this approach approximate calculation of tracer concentration at different times in producing well, and at a fixed time at various porous media points can be carried out.

A Comparison of Antibacterial Activity of Selected Thyme (Thymus) Species by Means of the Dot Blot Test with Direct Bioautographic Detection

Bioautography carried out with the aid of thin-layer chromatographic adsorbents can be used to assess antibacterial activity in samples of different origin. It can either be used as a simple and cost-effective detection method applied to a developed chromatogram, or to the dot blot test performed on a chromatographic plate, where total antibacterial activity of a sample is scrutinized. It was an aim of this study to compare antibacterial activity of 18 thyme (Thymus) specimens and species (originating from the same gardening plot and harvested in the same period of time) by means of a dot blot test with direct bioautography. A two-step extraction of herbal material was applied, and at step two the polar fraction of secondary metabolites was obtained under the earlier optimized extraction conditions [methanol–water (27 + 73, v/v), 130°C]. This fraction was then tested for its antibacterial activity against Bacillus subtilis bacteria. It was established that all investigated extracts exhibited antibacterial activity, yet distinct differences were perceived in the size of the bacterial growth inhibition zones among the compared thyme species. Based on the results obtained, T. citriodorus “golden dwarf” (sample No. 5) and T. marschallianus (sample No. 6) were selected as promising targets for further investigations and possible inclusion in a herbal pharmacopeia, which is an essential scientific novelty of this study.

Contribution to the TLC separation of ursolic and oleanolic acid mixture

Contribution to the TLC separation of ursolic and oleanolic acid mixtureThe aim of the study was to develop a rapid, simple, effective and reproducible TLC method for separation of a naturally occurring mixture of ursolic and oleanolic acids. Because of the similarity of chemical structures,in situderivatisation by iodine was necessary to separate these triterpenic acids. Separation was achieved on silica gel plates. After derivatisation, a chromatographic plate was developed with the mobile phase consisting of light petrol, ethyl acetate and acetone (8.2:1.8:0.1, v/v/v) following visualisation by spraying with sulphuric acid in diethylether (25%, v/v) and heating to 120°C for 5 min. The method used enabled chromatographical differentiation of ursolic and oleanolic acid mixtures in all tested mutual ratios.

Separation of Four Mixtures of Pesticides by Pressurized Planar Electrochromatography (PPEC)

Examples of separations of four mixtures of pesticides by pressurized planar electrochromatography (PPEC) under different operating conditions are presented. The samples were separated on a prewetted RP-18W chromatographic plate in a system with acetonitrilebuffer as the mobile phase. A potential of 2.3 kV was applied to a 10 cm long plate to create the electric field. Reproducible retention of pesticides was obtained during PPEC in the closed system when the sorbent layer of the plate was prewetted and equilibrated with the mobile phase. The reported separations of pesticides by PPEC are over 10 times faster than the corresponding separations by TLC.

Application of Overpressured Layer Chromatography Combined with Digital Autoradiography and Mass Spectrometry in the Study of Deramciclane Metabolism

Overpressured layer chromatography was combined with the highly sensitive and rapid digital autoradiography (DAR) and mass spectrometry to separate, detect, and identify 3H-and 14C-labeled deramciclane metabolites in different biological matrixes. Several minor and major metabolites were separated from plasma and urine samples. The radioactive metabolites localized by DAR were scraped from the thin-layer chromatographic plate and transferred to a mass spectrometer for structure identification. Several metabolites were isolated and characterized, including hydroxy-/V-des- methyl deramciclane, which is described in detail. The combination of techniques is efficient and has good sensitivity: about 2 μg metabolite from a biological matrix was isolated and identified this way.