Calorimetry and liquid chromatography: determination of enthalpies of transfer from mobile phase to stationary phase

2004 ◽  
Vol 424 (1-2) ◽  
pp. 157-163 ◽  
Author(s):  
Koji Urakami ◽  
Ken Hosoya ◽  
Anthony E. Beezer
Keyword(s):  
Liquid Chromatography ◽  
Stationary Phase ◽  
Mobile Phase ◽  
Enthalpies Of Transfer

scholarly journals A New Definition of the Stationary Phase Volume in Mixed-Mode Chromatographic Columns in Hydrophilic Liquid Chromatography

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4819
Author(s):  
Pavel Jandera ◽  
Tomáš Hájek
Keyword(s):  
Liquid Chromatography ◽  
Stationary Phase ◽  
Mobile Phase ◽  
Dominant Role ◽  
Accurate Determination ◽  
Adsorbed Water ◽  
Retention Data ◽  
Phase Volume ◽  
Mobile Phases

Polar columns used in the HILIC (Hydrophilic Interaction Liquid Chromatography) systems take up water from the mixed aqueous–organic mobile phases in excess of the water concentration in the bulk mobile phase. The adsorbed water forms a diffuse layer, which becomes a part of the HILIC stationary phase and plays dominant role in the retention of polar compounds. It is difficult to fix the exact boundary between the diffuse stationary and the bulk mobile phase, hence determining the column hold-up volume is subject to errors. Adopting a convention that presumes that the volume of the adsorbed water can be understood as the column stationary phase volume enables unambiguous determination of the volumes of the stationary and of the mobile phases in the column, which is necessary for obtaining thermodynamically correct chromatographic data in HILIC systems. The volume of the aqueous stationary phase, Vex, can be determined experimentally by frontal analysis combined with Karl Fischer titration method, yielding isotherms of water adsorbed on polar columns, which allow direct prediction of the effects of the composition of aqueous–organic mobile phase on the retention in HILIC systems, and more accurate determination of phase volumes in columns and consistent retention data for any mobile phase composition. The n phase volume ratios of 18 columns calculated according to the new phase convention strongly depend on the type of the polar column. Zwitterionic and TSK gel amide and amine columns show especially strong water adsorption.

Separation and Determination of Some Aromatic Sulfones by Reversed-Phase High-Performance Liquid Chromatography

1994 ◽  
Vol 59 (3) ◽  
pp. 569-574 ◽  
Author(s):  
Josef Královský ◽  
Marta Kalhousová ◽  
Petr Šlosar
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Mobile Phase ◽  
High Performance ◽  
Reversed Phase ◽  
Uv Spectra ◽  
Optimum Conditions ◽  
Linear Calibration ◽  
Technical Grade

The reversed-phase high-performance liquid chromatography of some selected, industrially important aromatic sulfones has been investigated. The chromatographic behaviour of three groups of aromatic sulfones has been studied. The optimum conditions of separation and UV spectra of the sulfones and some of their hydroxy and benzyloxy derivatives are presented. The dependences of capacity factors vs methanol content in mobile phase are mentioned. The results obtained have been applied to the quantitative analysis of different technical-grade samples and isomer mixtures. For all the separation methods mentioned the concentration ranges of linear calibration curves have been determined.

Determination of adenine nucleotides by the modified method of high-performance liquid chromatography

2021 ◽  
Vol 66 (3) ◽  
pp. 172-176
Author(s):  
Lyubov Borisovna Kalikova ◽  
E. R. Boyko
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Mobile Phase ◽  
High Performance ◽  
Adenine Nucleotides ◽  
Release Time ◽  
Chromatography Method ◽  
Rp Hplc ◽  
Standard Solutions

Adenine nucleotides (ATP, ADP and AMP) play a central role in the regulation of metabolism and energy: they provide the energy balance of the cell, determine its redox state, act as allosteric effectors of a number of enzymes, modulate signaling and transcription factors and activate oxidation or biosynthesis substrates. A large number of methods have been developed to determine the level of ATP, ADP and AMP, but the most universal and effective method for the separation and analysis of complex mixtures is the reversed-phase high-performance liquid chromatography method (RP-HPLC). The aim of this study is to determine the optimal conditions for the qualitative separation and quantitative determination of standard solutions of ATP (1 mmol/l), ADP (0,5 mmol/l) and AMP (0,1 mmol/l) by RP-HPLC. The degree of separation of adenine nucleotides was estimated by the time of peak output in the chromatogram. To achieve the goal, the following tasks were set: assess the effect of the temperature of the analysis on the separation and change of the release time of the analytes in the chromatogram; determine the most optimal composition of the mobile phase for the separation of ATP, ADP and AMP in the chromatogram (the content of the organic solvent in the solution); to identify the effect of pH of the mobile phase on the separation of standard solutions of adenine nucleotides; set the optimal molarity of the mobile phase for the separation of ATP, ADP and AMP in the chromatogram. It was found that the temperature of the analysis does not affect the quality of peak separation, while the composition and pH of the mobile phase have a significant effect on the complete and clear separation of the studied nucleotides in the chromatogram. It was determined that the analysis temperature of 37°C and the mobile phase of 0.05 M KH2PO4 (pH 6.0) are optimal for separating the peaks of adenine nucleotides.

scholarly journals RAPID ANALYTICAL METHOD FOR ASSAY DETERMINATION FOR PROCHLORPERAZINE EDISYLATE DRUG SUBSTANCES BY ULTRA PERFORMANCE LIQUID CHROMATOGRAPHY

2017 ◽  
Vol 9 (4) ◽  
pp. 118 ◽  
Author(s):  
Kishorkumar L. Mule
Keyword(s):  
Liquid Chromatography ◽  
Trifluoroacetic Acid ◽  
Analytical Method ◽  
Mobile Phase ◽  
Ultra Performance Liquid Chromatography ◽  
Drug Substance ◽  
Assay Method ◽  
Column Temperature ◽  
Drug Substances

Objective: To develop and validate new, simple and rapid assay method for Prochlorperazine edisylate drug substance by UPLC as per ICH guidelines.Methods: Ultra performance liquid chromatographic method was developed, optimized and validated on Acquity UPLC by using Acquity BDH300 C4 (100 x 2.1 mm) 1.7µ column. 3.85g ammonium acetate in 1000 ml of water add 0.5 ml trifluoroacetic acid and 1 ml triethylamine (Mobile phase A): 0.5 ml trifluoroacetic acid in 1000 ml acetonitrile mobile phase (Mobile phase B) with gradient program. Detector wavelength 254 nm and column temperature 30 °C.Results: Linearity study was carried out for prochlorperazine edisylate, linearity was calculated from 80 % level to 120% with respect to specification level. The correlation coefficient (r) = 0.999 was proved that the method is robust. The resolution between known impurities and Prochlorperazine edisylate found more than 2.5, it was evident from specificity test that Prochlorperazine edisylate peak are well separated from its related impurities, hence the method is specific. Prochlorperazine edisylate sample solution and mobile phase were found to be stable for at least 3 d.Conclusion: A new, simple and rapid method has been developed and validated for assay determination of prochlorperazine edisylate in drug substance by Ultra Performance Liquid Chromatography (UPLC). The analytical method was developed and validated as per ICH guidelines. The developed method can be used for the fast assay determination of prochlorperazine edisylate drug substances in research laboratories and in the pharmaceutical industry. 

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