scholarly journals Reversed-phase thin-layer chromatography behavior of aldopentose derivatives

2012 ◽  
Vol 66 (3) ◽  
pp. 365-372 ◽  
Author(s):  
Dragana Livaja-Popovic ◽  
Eva Loncar ◽  
Lidija Jevric ◽  
Radomir Malbasa
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Stationary Phases ◽  
Reversed Phase ◽  
Chromatographic Behavior ◽  
Log P ◽  
Retention Factors ◽  
Mobile Phases ◽  
Acetone Water ◽  
Layer Chromatography

Quantitative structure-retention relationships (QSRR) have been used to study the chromatographic behavior of some aldopentose. The behavior of aldopentose derivatives was investigated by means of the reversed-phase thin-layer chromatography (RP TLC) on the silica gel impregnated with paraffin oil stationary phases. Binary mixtures of methanol-water, acetone-water and dioxane-water were used as mobile phases. Retention factors, RM0, corresponding to zero percent organic modifier in the aqueous mobile phase was determined. Lipophilicity C0 was calculated as the ratio of the intercept and slope values. There was satisfactory correlation between them and log P values calculated using different theoretical procedures. Some of these correlations offer very good predicting models, which are important for a better understanding of the relationships between chemical structure and retention. The study showed that the hydrophobic parameters RM0 and C0 can be used as a measures of lipophilicity of investigated compounds.

scholarly journals Normal and reversed phase thin-layer chromatography of new 16, 17-secoestrone derivatives

2003 ◽  
Vol 68 (1) ◽  
pp. 57-64 ◽  
Author(s):  
Marijana Acanski ◽  
Suzana Jovanovic-Santa ◽  
Lidija Jevric
Keyword(s):  
Thin Layer ◽  
Stationary Phase ◽  
Thin Layer Chromatography ◽  
Silica Gel ◽  
Reversed Phase ◽  
Retention Behavior ◽  
Mobile Phases ◽  
Layer Chromatography

The retention behavior and separation ability of a series of new 16,17-secoestrone derivatives has been studied on silica gel, alumina and C-18 silica gel layers with non-aqueous and aqueous-organic mobile phases. The retention behavior and separation ability are discussed in terms of the nature of the solute, eluent and stationary phase.

Microchannel Thin Layer Chromatography with in situ Plate Scanning Micro-DRIFTS Detection Using Plain and Polybutadiene Modified Zirconia Stationary Phases

2002 ◽  
Vol 56 (8) ◽  
pp. 1059-1066 ◽  
Author(s):  
Beata A. Musial ◽  
André J. Sommer ◽  
Neil D. Danielson
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Diffuse Reflectance ◽  
Stationary Phases ◽  
Reversed Phase ◽  
Diffuse Reflectance Infrared ◽  
Layer Chromatography ◽  
Tlc Separation ◽  
Zirconia Stationary Phases

Thin layer chromatography (TLC) of various dyes is compared in microchannels packed with either bare zirconia (normal phase) or polybutadiene (PBD) modified zirconia (reversed phase). In situ micro-diffuse reflectance infrared Fourier transform spectroscopy (μDRIFTS) of the analyte spots is possible due to the low absorption background of both plain and PBD zirconia. An instrument coupling μDRIFTS with a motorized stage that could profile the microchannel TLC plate is developed. The retention order of anthracene and pyrene probes as a function of percent acetonitrile are generally as expected on PBD zirconia but opposite for plain zirconia. Impurities in technical grade methylene blue can be determined after TLC separation on plain zirconia. The separation and infrared identification of various dyes such as dichlorofluorescein and rhodamine B on PBD zirconia is improved using a mobile phase with an additive such as phosphate or dihexylamine that prevents band streaking.

scholarly journals STUDYING OF THE LIPOPHILICITY AND TOXICITY OF DIPHENYLACETAMIDE DERIVATIVES

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Suzana Apostolov ◽  
Đenđi Vaštag ◽  
Borko Matijević ◽  
Gorana Mrđan
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Reversed Phase ◽  
Biologically Active ◽  
Log P ◽  
Organic Modifiers ◽  
Modern Approach ◽  
Software Packages ◽  
Test Organisms ◽  
Layer Chromatography

Modern approach in the study of biologically active compounds includes the establishment of relationships between molecular structure, physicochemical properties and the behavior which studied compound can manifest in the biological medium. These examinantions are performed in the early stages of the design of future bioactive agent and require the knowledge of molecular descriptors that can point to its biological activity, including lipophilicity which occupies a key position. For the series of diphenylacetamide derivatives, lipophilicity is determined experimentally by thin-layer chromatography on reversed phase (RP TLC18 F254s), in mixtures of water and various organic modifiers and computationally, by using the relevant software packages. In order to estimate the potential acute toxicity of the tested diphenylacetamide derivatives, their effective concentrations, EC50, on the selected test organisms have been determined. Experimentally determined lipophilicity (RM 0 and m) is correlated with a standard measure of lipophilicity (log P), as well as with the selected parameters of toxicity. Thus it has been found that thin-layer chromatography on reversed phase can be used reliably for describing the lipophilicity and for the evaluation of the toxic effects of diphenylacetamide derivatives.

scholarly journals Thin-layer chromatography of L-carnitine in micellar and cyclodextrin mobile phases

2019 ◽  
Vol 58 (5) ◽  
pp. 62-69
Author(s):  
Anna O. Ustyugova ◽  
◽  
Elena G. Sumina ◽  
Varsenia Z. Uglanova ◽  
Olga N. Novozhilova ◽  
...  
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Separation Efficiency ◽  
Sodium Dodecyl ◽  
Theoretical Plate ◽  
Process Efficiency ◽  
Chromatographic Behavior ◽  
Mobile Phases ◽  
Wide Range ◽  
Layer Chromatography

L-carnitine (lat. Levocarnitinum, eng. Levocarnitine) is a natural substance akin to B vitamins. Normalizing metabolic processes in the human body and having a wide range of therapeutic actions, L-carnitine is widely used in cardiology, neurology, gastroenterology, and sports medicine. Currently, modern analytical techniques, such as mass spectrometry, high performance liquid chromatography, radiation methods, etc., are used to analyze L-carnitine. Most of them are rather expensive and time consuming. Thin-layer chromatography (TLC), which is notable for its simplicity, feasibility of analysis, separation efficiency and low cost, has received much less use. In this regard, the purpose of this work was to reveal the analytical capabilities of water-organic, micellar and cyclodextrin mobile phases for the analysis of L-carnitine by means of TLC. Initial L-carnitine solutions with a concentration of 20 mg/ml were prepared by diluting solutions for injections. Their chromatography was carried out by ascending thin-layer chromatography on plates of various polarities (Sorbfil, Plasmachrom, and RP-18) with a fixed sorbent layer. Aqueous solutions of surfactants (cetyltrimethylammonium bromide, cetylpyridinium chloride, sodium dodecyl sulfate, Triton X-100), of cyclodextrins (-cyclodextrin, 2-hydroxypropyl--cyclodextrin), hydroxypropyl--cyclodextrin) were used as mobile phases. The zone of the main substance (L-carnitine) was identified by treating the plate with a mixture of freshly prepared 0.1N solution of potassium permanganate and 2.0 N acetic acid (the zone was colored in a light yellow color). Main features of the chromatographic behavior of L-carnitine were revealed. Based on the calculation of the number of theoretical plates and the height equivalent to one theoretical plate, it was shown that aqueous micellar and cyclodextrin mobile phases allow one to improve the chromatographic process efficiency and the shape of the chromatographic zones of L-carnitine as compared to water-organic eluents; cheaper Sorbfil plates (Russia) can be used for practical purposes. Optimal chromatographic systems and conditions for their use in the thin-layer chromatography of pharmaceuticals and food products have been selected and substantiated.

scholarly journals Reversed-phase thin-layer chromatography of some angiotensin converting enzyme (ACE) inhibitors and their active metabolites

2006 ◽  
Vol 71 (6) ◽  
pp. 621-628 ◽  
Author(s):  
Jadranka Odovic ◽  
Biljana Stojimirovic ◽  
Mirjana Aleksic ◽  
Dusanka Milojkovic-Opsenica ◽  
Zivoslav Tesic
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Ace Inhibitors ◽  
Reversed Phase ◽  
Log P ◽  
Binary Solvent ◽  
Active Metabolites ◽  
Solvent Systems ◽  
Layer Chromatography ◽  
Lipophilicity Parameters

The chromatographic behaviour of some ACE inhibitors and their active metabolites was examined under conditions of reversed-phase thin-layer chromatography on RP-18 silica using water-methanol, water-ethanol and water-acetone as binary solvent systems. The relationship between the R M values and the concentration of organic modifier in the mobile phases was linear. It was found that an increase in the content of the organicmodifier in the employed solvent systems led to a decrease of the R M values, i.e., of the retention. Also, the more hydrophobic compounds had a longer retention. Based on regression analysis of the plots, the lipophilicity parameters R M 0 and c 0 were calculated. The chromatographically obtained lipophilicity parameters were correlated with the calculated log P values.

scholarly journals Reversed-Phase Thin-Layer Chromatography with Different Stationary Phases in Studies of Quantitative Structure–Biological Activity Relationship of New Antimycotic Compounds

1999 ◽  
Vol 82 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Jan K Rózylo ◽  
Anna Zabiñska ◽  
Joanna Matysiak ◽  
Andrzej Niewiadomy
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Stationary Phases ◽  
Quantitative Structure Activity Relationship ◽  
Reversed Phase ◽  
Activity Relationship ◽  
Quantitative Structure ◽  
Acetone Concentration ◽  
Qsar Studies ◽  
Layer Chromatography

Abstract Reversed-phase thin-layer chromatography with RP-8, RP-18, and RP-18W stationary phases was used in quantitative structure–activity relationship (QSAR) studies of new antimycotic compounds. The retention behavior of 10 dihydroxythioben-zanilides was examined for acquisition of log k data. With water–acetone mixtures as the mobile phases, the concentration range for which the correlation between log k′ and acetone concentration is linear was established for each stationary phase and used to determine hydrophobicity parameters log k′w by linear extrapolation. The effect of substituents on retention constants was quantitated by using the group contribution parameters τw. On the basis of QSAR equations obtained from these studies, log k′w, data can be used to predict antifungal activities of dihydroxythiobenzanilides with satisfactory accuracy.

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