Chromatography kinetic theory

Poole, C.F. Kinetic Theory of Planar Chromatography. In Planar Chromatography. A Retrospective View for the Third Millennium Nyiredy, Sz., Ed. Springer Budapest, 2001 13-32. 

Kinetic theories. These theories take account of the influence of flow conditions, of diffusion and of the mass transfer resistance on the spreading of a chromatographic peak. Gas-liquid and gas-solid chromatographies are approached in different ways and are therefore treated separately. 

A. Gas-liquid chromatography. The most important of the kinetic theories describing the processes in the chromatographic column in GLC are those of Lapidus and Amundson [24], Glueckauf [25], Klinkenberg and Sjenitzer [26] and van Deemter et al. [27]. ... 

In the rate theory of gas-solid chromatography, the equation for h has essentially the same terms except that Cj, replaces C . Ck is a term characteristic of adsorption kinetics. Equation... 

Giddings, J. C. (1965). Diffusion and kinetics and chromatography. In Dynamics of Chromatography Principles and Theory (Giddings, J. C. Ed.). Marcel Dekker, New York, pp. 217-225. 

Theory of Gas-Solid Chromatography Potential for Analytical Use and the Study of Surface Kinetics, J. C. Giddings, Anal. Chem., 36, 1170 (1964). 

A high electroosmotic flow through the stationary-phase particles may be created when the appropriate conditions are provided. This pore flow has important consequences for the chromatographic efficiency that may be obtained in CEC. From plate height theories on (pressure-driven) techniques such as perfusion and membrane chromatography, it is known that perfusive transport may strongly enhance the stationary-phase mass transfer kinetics [30-34], It is emphasised... 

All of the theories that have just been mentioned were put forward at a time when few experimental details had been established for pyrolyses in the gas phase. During the past few years powerful techniques, particularly those of gas-liquid chromatography and mass spectrometry, have been developed, so that it is now possible to study the kinetics of formation of the minor products. 

This book covers the theory, development, and application in considerable detail and describes the history of development of Ion exchange materials and the advances in their utilization in industrial processes. Key applications in such areas as water purification, hydrometallurgy, and chromatography are described and supported by chapters on the related scientific fundamentals governing equilibria and kinetics of Ion exchange. 

The rate theory examines the kinetics of exchange that takes place in a chromatographic system and identifies the factors that control band dispersion. The first explicit height equivalent to a theoretical plate (HETP) equation was developed by Van Deemter et al. in 1956 [1] for a packed gas chromatography (GC) column. Van Deemter et al. considered that four spreading processes were responsible for peak dispersion, namely multi-path dispersion, longitudinal diffusion, resistance to mass transfer in the mobile phase, and resistance to mass transfer in the stationary phase. 

In his nonequilibrium theory of chromatography, Giddings [67] attempted to derive a general relationship between the broadening of a chromatographic zone due to the mass transfer kinetics and the experimental parameters. Central to his approach, however, is the recognition that the two phases of the chromatographic column are always near equilibrium. 

For all these reasons, the mathematical aspects of the theory become much more complex. The mathematics of nonlinear chromatography are so complex that even for a single solute, there is no analytical, closed-form solution available, except with two simplified models, the ideal model and the Thomas model [120]. The ideal model is based upon the assumption of an infinite column efficiency. Its solutions are discussed in detail in Chapters 7 to 9. The Thomas model is based upon the assumptions that there is a slow Langmuir adsorption-desorption kinetics and that there are no other nvass transfer resistances, nor any axial dispersion. The system of equations of this model has been solved by Goldstein [121], and this general solution has been simplified for pulse injection by Wade et al. [122]. In aU other cases, the problem must be solved numerically. The Thomas model is discussed with other kinetic models in Chapter 14 and 16. 

As discussed already in Chapter 2 (Section 2.2.6), Giddings [10] has developed a nonequilibrium theory of chromatography and showed that the influence of the kinetics of mass transfers can be treated as a contribution to axial dispersion. As illustrated in Chapter 6, this approximation is excellent in linear chromatography, as long as the column efficiency exceeds 20 to 30 theoretical plates. 

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