Characterisation of reversed-phase stationary phases for the liquid chromatographic analysis of basic pharmaceuticals by thermodynamic data
| Autor: | A.J.J. Debets, R.J.M. Vervoort, G.J. de Jong, E. Ruyter, C.A.M.G. Cramers, Henk A. Claessens |
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| Přispěvatelé: | Groningen Research Institute of Pharmacy, Chemical Engineering and Chemistry |
| Jazyk: | angličtina |
| Rok vydání: | 2002 |
| Předmět: |
Standard molar entropy
Tertiary amine LC Enthalpy Biochemistry High-performance liquid chromatography Analytical Chemistry stationary phases Entropy (classical thermodynamics) Column chromatography RETENTION Physics::Chemical Physics thermodynamic parameters Chromatography Chemistry Organic Chemistry General Medicine Reversed-phase chromatography N N-dimethyloctylamine Standard enthalpy of formation basic drugs Pharmaceutical Preparations TEMPERATURE-DEPENDENCE COLUMN Thermodynamics BEHAVIOR Chromatography Liquid |
| Zdroj: | Journal of Chromatography A, 964(1-2):PII S0021-9673(02)00589-7, 67-76. ELSEVIER SCIENCE BV Journal of Chromatography, A, 964(1-2), 67-76. Elsevier |
| ISSN: | 0021-9673 |
| Popis: | This paper describes the characterisation of reversed-phase liquid chromatography (RPLC) columns using thermodynamic measurements. Retention versus I IT data were used to construct Van't Hoff plots. The slope of these plots indicates the standard enthalpy of transfer of the analyte from the mobile to the stationary phase. The standard entropy can be calculated from the intercept. Van't Hoff plots were linear for the investigated RPLC columns, meaning that for basic analytes over the temperature range studied no changes in the retention mechanism occurred. Enthalpies and entropies of transfer of basic analytes from the mobile to the stationary phase revealed information about the types of interaction of protonated and neutral compounds with the stationary phases. However. a clear view using the present set of basic compounds on how these thermodynamic data may explain the observed substantial differences in peak symmetry cannot be given, It is considered that addition of N,N-dimethyloctylamine (DMOA) to the eluent will results in a dynamically coating of the stationary phase. Addition of DMOA to the eluent resulted for protonated basic compounds in a reduction of both enthalpy and entropy. In practice, with DMOA in the eluent symmetrical peaks were obtained. It is assumed that this is due to blocking residual silanols and/or ion exclusion effects. (C) 2002 Elsevier Science B.V. All rights reserved. |
| Databáze: | OpenAIRE |
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