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.

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.

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.

Hydrophilic Interaction Liquid Chromatography and Per Aqueous Liquid Chromatography in Fungicides Analysis

2012 ◽  
Vol 95 (5) ◽  
pp. 1362-1370 ◽  
Author(s):  
Sylwia Noga ◽  
Attila Felinger ◽  
Bogusław Buszewski
Keyword(s):  
Liquid Chromatography ◽  
Organic Solvent ◽  
Mobile Phase ◽  
Retention Mechanism ◽  
Operating Conditions ◽  
Biologically Active ◽  
Hydrophilic Interaction Liquid Chromatography ◽  
Hydrophilic Interaction ◽  
Active Compounds ◽  
Retention Mechanisms

Abstract The goal of the study was to investigate the retention mechanism of selected fungicides in hydrophilic interaction liquid chromatography (HILIC) and per aqueous liquid chromatography (PALC). Chromatographic measurements were made on four physicochemically diversified HILIC columns, which were evaluated for the analysis of nine biologically active compounds, such as strobilurins and triazoles. The effects of the operating conditions on separations were investigated, including the concentration of the organic solvent in the aqueous-organic (acetonitrile) mobile phase. The results were compared, and it was shown that two different retention mechanisms dominate in PALC at low acetonitrile concentrations and in HILIC at high acetonitrile concentrations.

scholarly journals Retention behaviour of some estradiol derivatives on alumina in normal phase chromatrography

2003 ◽  
Vol 68 (3) ◽  
pp. 163-170 ◽  
Author(s):  
Marijana Acanski
Keyword(s):  
Mobile Phase ◽  
Volume Fraction ◽  
Retention Behavior ◽  
Relative Retention ◽  
Linear Relationships ◽  
Mobile Phases ◽  
Binary Mobile Phases ◽  
Estradiol Derivatives ◽  
Rf Values ◽  
The Relationship

The retention constants of variously substituted estradiol derivatives were measured as a function of the composition of various binary mobile phases in order to study the relationship between chemical structure and retention behavior in TLC on alumina. The slopes and intercepts of the linear relationships between the retention constant RM and the logarithm of the volume fraction of the polar mobile phase component were calculated and are discussed in relation to the characteristics of the solute and mobile phase. The RF values and relative retention ?RM of the compounds depend largely on the retention behavior of their substituents. The results obtained in this investigation are compared with the results of the same derivatives obtained in previous investigations on silica gel.

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 Analysis of Some Biogenic Amines by Micellar Liquid Chromatography

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Irena Malinowska ◽  
Katarzyna E. Stępnik
Keyword(s):  
Liquid Chromatography ◽  
Sodium Dodecyl Sulfate ◽  
Biogenic Amines ◽  
Physicochemical Parameters ◽  
Mobile Phase ◽  
Sodium Dodecyl ◽  
Micellar Liquid Chromatography ◽  
Ionic Surfactant ◽  
Mobile Phases ◽  
Dodecyl Sulfate

Micellar liquid chromatography (MLC) with the use of high performance liquid chromatography (HPLC) was used to determine some physicochemical parameters of six biogenic amines: adrenaline, dopamine, octopamine, histamine, 2-phenylethylamine, and tyramine. In this paper, an influence of surfactant’s concentration and pH of the micellar mobile phase on the retention of the tested substances was examined. To determine the influence of surfactant’s concentration on the retention of the tested amines, buffered solutions (at pH 7.4) of ionic surfactant—sodium dodecyl sulfate SDS (at different concentrations) with acetonitrile as an organic modifier (0.8/0.2 v/v) were used as the micellar mobile phases. To determine the influence of pH of the micellar mobile phase on the retention, mobile phases contained buffered solutions (at different pH values) of sodium dodecyl sulfate SDS (at 0.1 M) with acetonitrile (0.8/0.2 v/v). The inverse of value of retention factor () versus concentration of micelles () relationships were examined. Other physicochemical parameters of solutes such as an association constant analyte—micelle ()—and partition coefficient of analyte between stationary phase and water (hydrophobicity descriptor) () were determined by the use of Foley’s equation.

Detection, Quantitation, and Identification of Residual Aminopenicillins by High-Performance Liquid Chromatography after Fluorescamine Derivation

2000 ◽  
Vol 63 (10) ◽  
pp. 1421-1425 ◽  
Author(s):  
CHIH-CHUN HONG ◽  
FUSAO KONDO
Keyword(s):  
Bovine Serum ◽  
Mobile Phase ◽  
High Performance ◽  
Serum Proteins ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Excitation Wavelength ◽  
Column Temperature ◽  
Solid Phase Extraction Cartridge ◽  
Mobile Phases

A high-performance liquid chromatographic (HPLC) method with fluorescence detection after precolumn fluorescamine derivation was developed to detect residues of two aminopenicillins, amoxicillin (AMPC) and ampicillin (ABPC), in bovine serum. Proteins in serum samples spiked with each of these penicillins were precipitated with sodium tungstate and sulfuric acid, centrifuged, and removed by passage through a C18 solid-phase extraction cartridge. After precolumn treatment of the extraction products of AMPC and ABPC with fluorescamine solution, HPLC analysis with fluorescence spectrophotometric detection at an excitation wavelength of 390 nm and an emission wavelength of 485 nm was performed to identify these products. Two mobile phases were used for residual analysis by the isocratic HPLC system. An ODP column (polyvinyl alcohol bonded with an octadecyl functional group) that can be used with strongly alkaline mobile phases (pH 2.0 to 13) was selected, and the column temperature was set at 40°C. A mobile phase comprising 100-mM K2HPO4 solution and acetonitrile (72:28, vol/vol), which yielded AMPC and ABPC retention times of 4.1 and 7.9 min, respectively, was suitable for detection of residual ABPC but not for residual AMPC because interference was caused by peaks of other extracted substances. When a mobile phase comprising a different ratio of 100-mM K2HPO4 solution and acetonitrile (78:22, vol/vol) was used, the retention times of AMPC and ABPC were 7.3 and 26.3 min, respectively, and both penicillins could be analyzed using this system. The calculated standard curves of the reaction products with both mobile phases were linear, and the correlation coefficients were greater than 0.999. The lower limit of detection was 10 ng/ml for both penicillins. Analysis of extracts from bovine serum spiked with AMPC and ABPC at a concentration of 1 μg/ml yielded recovery rates of 102.2 ± 5.5% and 79.0 ± 5.2%, respectively. This detection method may be useful for routine laboratory testing of AMPC and ABPC.

MAGIC-LC/FT-IR Spectrometry: Preliminary Studies

1988 ◽  
Vol 42 (8) ◽  
pp. 1365-1368 ◽  
Author(s):  
R. M. Robertson ◽  
J. A. De Haseth ◽  
J. D. Kirk ◽  
R. F. Browner
Keyword(s):  
Phase Composition ◽  
Mobile Phase ◽  
Mobile Phase Composition ◽  
Reverse Phase ◽  
Ir Spectrometry ◽  
Aerosol Generation ◽  
Mobile Phases ◽  
Ft Ir ◽  
Effluent Stream ◽  
Phase Water

A new solvent elimination interface based on the Monodisperse Aerosol Generation Interface for Combining Liquid Chromatography with Fourier transform infrared (MAGIC-LC/FT-IR) spectrometry is described. The solvent elimination efficiency of MAGIC-LC/FT-IR was studied by varying the mobile-phase composition from 100% methanol to 100% water. As the mobile-phase composition was varied, erythrosin B was injected into the interface and deposited on a KBr window after the solvent removal. Spectra were obtained which compared favorably with reference spectra, even as the mobile-phase water content was increased. A reverse-phase separation was completed to demonstrate that readily identifiable spectra can be obtained from mobile phases containing high percentages of water, without heating of the effluent stream.

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