Unified Theory of Absorption Chromatography: Gas, Liquid, and Supercritical Fluid Mobile Phases

Martire, Daniel E.

doi:10.1080/01483918708066788

Cited by 42 publications

(15 citation statements)

References 12 publications

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“…In most of the above-cited models for the pressure and temperature effects on SFC retention, the effect of swelling has been ignored although its importance has already been emphasized in the early studies on high-pressure GC [127-1311. With a specific reference to SFC, the effect of swelling on solute retention has been taken into account in the unified molecular theory of both partition [105,132] and adsorption [133-1351 chromatography, and in several treatments employing classical thermodynamics [76,77,88,90,91]. The unified molecular theory of chromatography is based on a mean-field lattice-gas model comprising the approximation of random mixing.…”

Section: Enhancement Factors Brown Et Al [71]mentioning

confidence: 99%

Diffusion and thermodynamic measurements by supercritical fluid chromatography

Roth

1991

J Microcolumn Separations

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Abstract. Applications of supercritical fluid chromatography (SFC) to physicochemical measurements are reviewed. Emphasis is laid on the determination of binary diffusion coefficients at infmite dilution of solutes in supercritical solvents, and on actual or potential applications of SFC to the measurements of thermodynamic quantities in dilute, binary, supercritical mixtures. Physicochemical measurements emerge as a specific application field of SFC with many links to transport phenomena and to molecular thermodynamics of fluid-phase equilibria. Key words: supercritical fluid chromatography, d i p i v i t y measurements, diDsioncoescients, thermodynamic measurements, dilute supercritical mixtures

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Section: Enhancement Factors Brown Et Al [71]mentioning

confidence: 99%

Diffusion and thermodynamic measurements by supercritical fluid chromatography

Roth

1991

J Microcolumn Separations

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“…These measurements are presently under evaluation, whereby plate height versus line_ velocity graphs are in preparation for each solute• These graphs, and the hydrodynamic data derived therefrom, may then be compared with the most rigorous theoretical models (13). Two features in this comparison are of particular interest: First, we wish to examine the dependence of longitudinal diffusion and mass transfer contributions on temperature and pressure• While this dependence has been addressed for gas and supercritical-fluid chromatography (13,32,33), it has not been adequately characterized in liquid chromatography. This dependence becomes particularly important if the stationary phase undergoes a phase transition along the chromatographic column (vide supra).…”

Section: /?mentioning

confidence: 99%

Direct probing of chromatography columns by laser-induced fluorescence

McGuffin¹

1992

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This report summarizes the progress and accomplishments of this research project from September 1, 1989 to February 28, 1993. During this period, we have accomplished ali of the primary scientific objectives of the research proposal: 1) constructed and evaluated a laser-induced fluorescence detection system that allows direct examination of the chromatographic column, 2) examined nonequilibrium processes that occur upon solute injection and elution, 3) examined solute retention in liquid chromatography as a function of temperature and pressure, 4) examined solute zone dispersion in liquid chromatography as a function of temperature and pressure, and 5) developed appropriate theoretical models to describe these phenomena. In each of these studies, substantial knowledge has been gained of the fundamental processes that are responsible for chromatographic separations. lr, addition to these primary research objectives, we have made significant progress in three related areas: 1) examined pyrene as a fluorescent polarity probe in supercritical fluids and liquids as a function of temperature and pressure, 2) developed methods for the class-selective identification of polynuclear aromatic hydrocarbons in coal-derived fluids by microcolumn liquid chromatography with fluorescence quenching detection, and 3) developed methods for the determination of saturated and unsaturated (including omega-3) fatty acids in fish oil extracts by microcolumn liquid chromatography with laser-induced fluorescence detection. In these studies, the advanced separation and detection techniques developed in our laboratory are applied to practical problems of environmental and biomedical significance.

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“…The importance of pressure in liquid chromatography was first demonstrated in the late 1960s when Giddings (35,36) developed supercritical-fluid chromatography. A complete mathematical formulation of the pressure/ temperature equilibrium shifts in chromatographic separations was proposed later by Martire (37,38) in the framework of the unified molecular theory of chromatography (UMTC). Unfortunately, the UMTC theory and other molecular models (39)(40)(41)(42) have had, so far, a limited practical impact on the investigation of the influence of the pressure on the solute retention behavior in HPLC.…”

Section: Introductionmentioning

confidence: 99%

True and Apparent Temperature Dependence of Protein Adsorption Equilibrium in Reversed‐Phase HPLC

Szabelski

Cavazzini

Kaczmarski

et al. 2002

Biotechnology Progress

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The adsorption behavior of bovine insulin on a C(8)-bonded silica stationary phase was investigated at different column pressures and temperatures in isocratic reversed-phase HPLC. Changes in the molar volume of insulin (deltaV(m)) upon adsorption were derived from the pressure dependence of the isothermal retention factor (k'). The values of deltaV(m) were found to be practically independent of the temperature between 25 and 50 degrees C at -96 mL/mol and to increase with increasing temperature, up to -108 mL/mol reached at 50 degrees C. This trend was confirmed by two separate series of measurements of the thermal dependence of ln(k'). In the first series the average column pressure was kept constant. The second series involved measurements of ln(k') under constant mobile-phase flow rate, the average column pressure varying with the temperature. In both cases, a parabolic shape relationship was observed between ln(k') and the temperature, but the values obtained for ln k' were higher in the first than in the second case. The relative difference in ln(k'), caused by the change in pressure drop induced by the temperature, is equivalent to a systematic error in the estimate of the Gibbs free energy of 12%. Thus, a substantial error is made in the estimates of the enthalpy and entropy of adsorption when neglecting the pressure effects associated with the change in the molar volume of insulin. This work proves that the average column pressure must be kept constant during thermodynamic measurements of protein adsorption constants, especially in RPLC and HIC. Our results show also that there is a critical temperature, T(c) approximately equals 53 degrees C, at which ln(k') is maximum and the insulin adsorption process changes from an exothermic to an endothermic one. This temperature determines also the transition point in the molecular mechanism of insulin adsorption that involves successive unfolding of the protein chain.

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Unified Theory of Absorption Chromatography: Gas, Liquid, and Supercritical Fluid Mobile Phases

Cited by 42 publications

References 12 publications

Diffusion and thermodynamic measurements by supercritical fluid chromatography

Diffusion and thermodynamic measurements by supercritical fluid chromatography

Direct probing of chromatography columns by laser-induced fluorescence

True and Apparent Temperature Dependence of Protein Adsorption Equilibrium in Reversed‐Phase HPLC

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