scholarly journals Chromatographic behavior and lipophilicity of s-triazine derivatives on silica gel impregnated with paraffin oil

2010 ◽  
pp. 159-168 ◽  
Author(s):  
Lidija Jevric ◽  
Gordana Koprivica ◽  
Nevena Misljenovic ◽  
Bratislav Jovanovic
Keyword(s):  
Silica Gel ◽  
Volume Fraction ◽  
Reversed Phase ◽  
Retention Mechanism ◽  
Chromatographic Behavior ◽  
Oil Retention ◽  
Paraffin Oil ◽  
Mobile Phases ◽  
Acetone Water ◽  
Triazine Derivatives

The chromatographic behavior of four group of s-triazine derivatives (14 compounds) has been studied by TLC on silica gel impregnated with paraffin oil. Retention mechanism has been determined using the following mobile phases: water-acetone, water-acetonitrile, water-dioxane, water-tetrahydrofuran, water-methanol and water-ethanol, by changing the volume fraction of modifier in the mobile phase. On impregnated silica gel, a reversed-phase chromatographic process occurs. Good correlation was obtained between the retention constants, RM 0 (determined by linear extrapolation), and slope, S, of chromatographic equations. There was also satisfactory correlation between these retention constants and logP values calculated using different theoretical methods. The study showed that the retention constants can be used as a measure of lipophilicity of investigated compounds.

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 Reversed-phase HPLC retention data in correlation studies with in lipophilicity molecular descriptors of carotenoids

2013 ◽  
Vol 67 (6) ◽  
pp. 933-940 ◽  
Author(s):  
Sanja Podunavac-Kuzmanovic ◽  
Lidija Jevric ◽  
Aleksandra Tepic ◽  
Zdravko Sumic
Keyword(s):  
Predictive Ability ◽  
Reversed Phase ◽  
Retention Mechanism ◽  
Chromatographic Behavior ◽  
Retention Data ◽  
Nonlinear Structure ◽  
Software Products ◽  
Acetone Water ◽  
Paprika Oleoresin ◽  
Predicted Values

Influence of chemical structure on the lipophilicity of isolated free carotenoids from paprika oleoresin has been studied by QSRR approach (Quantitative structure-retention relationship). The chromatographic behavior of these compounds was investigated by using reversed phase high-pressure liquid chromatography (RP HPLC). Retention mechanism has been determined using the following mobile phase: acetone -water, on reversed - phase column (SB-C18). A variety of lipophilicity parameters (logP) were calculated by use of different software products. On the basis of correlations, the nonlinear structure-activity models were derived between the retention constants, tr (retention time of investigation compounds), and logP values. Five high quality QSRR models were found to have a good predictive ability and close agreement between experimental and predicted values. The study showed that the retention constants can be used as a measure of lipophilicity of investigated compounds at a high significant level.

scholarly journals Estimation of Solute-Stationary Phase and Solute-Mobile Phase Interactions in the Presence of Ionic Liquids

Separations ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 40
Author(s):  
María José Ruiz-Ángel
Keyword(s):  
Ionic Liquids ◽  
Stationary Phase ◽  
Mobile Phase ◽  
Stationary Phases ◽  
Reversed Phase ◽  
Retention Mechanism ◽  
Chromatographic Behavior ◽  
Chemical Equilibria ◽  
Suppression Effect ◽  
Mobile Phases

The presence of free silanols on alkyl-bonded reversed-phase stationary phases is responsible for broad and asymmetrical peaks when basic drugs are chromatographed with conventional octadecylsilane (C18) columns due to ionic interactions. In the last few years, ionic liquids (ILs) have attracted attention to reduce this undesirable silanol activity. ILs should be considered as dual modifiers (with a cationic and anionic character), which means that both cations and anions are able to adsorb on the stationary phase, creating a positively or negatively charged layer, depending on the relative adsorption. The accessibility of basic compounds to the silanols is prevented by both the IL cation and anion, improving the peak profiles. A comparative study of the performance of six imidazolium-based ILs, differing in their cation/anions, as modifiers of the chromatographic behavior of a group of ten β-adrenoceptor antagonists, is addressed. Mobile phases containing cationic amines (triethylamine and dimethyloctylamine) were used as a reference for the interpretation of the results. Using a mathematical model based on two chemical equilibria, the association constants between the solutes and modified stationary phase as well as those between solutes and the additive in the mobile phase were estimated. These values, together with the changes in retention and peak shape, were used to obtain conclusions about the retention mechanism, changes in the nature of the chromatographic system, and silanol suppression effect.

scholarly journals Retention behaviour of acyclic polyfunctional D-arabinose derivatives

2002 ◽  
pp. 35-44 ◽  
Author(s):  
Ljiljana Kolarov ◽  
Eva Loncar ◽  
Radomir Malbasa
Keyword(s):  
Mobile Phase ◽  
Volume Fraction ◽  
Retention Mechanism ◽  
Biologically Active ◽  
Polar Component ◽  
Chiral Molecules ◽  
Retention Behaviour ◽  
Polar Components ◽  
Solute Retention ◽  
Mobile Phases

It is well known that some of biologically active compounds are chiral molecules. Natural monosaccarides are applicable as chiral precursors. D-arabinose is an appropriate chiral precursor in the synthesis of very important biomolecules such as biotin and its analogues and feromon )-exobrevicomin. Acyclic poly functional D- arabinose derivatives are intermediates in the synthesis of the former biomolecules. This paper deals with the retention behaviour and retention mechanism of acyclic poly functional D-arabinose derivatives. The tested compounds have been chromato graphed on silica gel thin layer using binary organic mobile phases with a different polarity. With increasing polarity of the eluent polar components the solute retention is decreasing. The linear relationship is obtained between the values of retention constant, RM' and the logarithm of the mobile phase polar component volume fraction for all solutes tested and eluents used.

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.

A contribution to the description of the retention mechanism of metal chelates during their reversed-phase chromatography

1985 ◽  
Vol 50 (10) ◽  
pp. 2221-2227 ◽  
Author(s):  
František Vláčil ◽  
Věra Hamplová
Keyword(s):  
Mobile Phase ◽  
Volume Fraction ◽  
Reversed Phase ◽  
Metal Chelates ◽  
Retention Mechanism ◽  
Aqueous Mixtures ◽  
Liquid Liquid Extraction ◽  
Bonded Phase ◽  
Binary Mobile Phase ◽  
Phase Liquid

Mercury(II) diethyldithiocarbamate was chromatographed on silica gel with chemically bonded octadecyl groups using aqueous mixtures with methanol, acetonitrile, dioxane, and tetrahydrofuran, respectively, as the mobile phase, and the dependence of logarithm of the capacity ratio (k) on the volume fraction of water in the binary mobile phase was examined. Also, the dependence of k on the liquid-liquid extraction distribution ratio in an aqueous methanol-n-alkane extraction system was investigated for Cu, Co, Ni, Pb, and Hg diethyldithiocarbamates. Both kinds of dependence are linear, which suggests that the retention of the electroneutral metal chelates during the reversed-phase liquid chromatography on a nonpolar chemically bonded phase is due to the solvophobic effect.

scholarly journals Retention behaviour of estradiol derivatives in reversed phase HPLC

2005 ◽  
pp. 169-178
Author(s):  
Marijana Acanski ◽  
Slobodan Petrovic
Keyword(s):  
Linear Relationship ◽  
Silica Gel ◽  
Mobile Phase ◽  
Volume Fraction ◽  
Reversed Phase ◽  
Considerable Effect ◽  
Reversed Phase Hplc ◽  
Retention Behaviour ◽  
Estradiol Derivatives ◽  
Octadecyl Silica Gel

Retention behaviour ofestradiol derivatives has been studied by the reversed phase HPLC. LiChrosorb RP-18 column end eluents consisting of methanol respectively aceto-nitrile and water in various proportions, were used. It was shown that there is a linear relationship between the retention constant and the volume fraction of organic component in the mobile phase. The slopes and intercepts of lines are in agreement with the polarity of derivatives studied. Considerable effect on the chromatographic behaviour exerted the type and position of substituents in the molecule of estradiol derivative. Results obtained in these investigations are compared with results of the same derivatives obtained in previous investigations on octadecyl silica gel in TLC with eluent methanol-water in various proportions.

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