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Title: Rate constants of mass transfer kinetics in reversed phase liquid chromatography

Abstract

The parameters of the kinetics of mass transfer of several n-alkylbenzenes were measured by the method of moments on a series of columns prepared with different samples of the same RPLC packing material having widely different average particle diameters, from 3 to 50 {micro}m. These data were analyzed using the available models, and correlations. The best agreement between experimental and theoretical data was obtained under the assumption that the rate constant for the external mass transfer increases with increasing average particle size, an unexpected conclusion. It was also shown that the interpretation of the relative importance of the roles of pore diffusivity and surface diffusivity in the internal mass transfer kinetics is somewhat ambiguous and that the conclusion to be drawn from experimental results depends on the assumptions made regarding the tortuosity model and the relationship between k{sub ext} and the average particle size.

Authors:
 [1];  [1];  [2];  [3]
  1. University of Tennessee, Knoxville (UTK)
  2. ORNL
  3. University of Tennessee and Rzeszow University of Technology, Poland
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
989572
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIChE Journal; Journal Volume: 51; Journal Issue: 12
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; LIQUID COLUMN CHROMATOGRAPHY; KINETICS; MASS TRANSFER; PARTICLE SIZE; AROMATICS; MATHEMATICAL MODELS

Citation Formats

Hong, Lan, Gritti, Fabrice, Guiochon, Georges A, and Kaczmarski, Krzysztof. Rate constants of mass transfer kinetics in reversed phase liquid chromatography. United States: N. p., 2005. Web. doi:10.1002/aic.10565.
Hong, Lan, Gritti, Fabrice, Guiochon, Georges A, & Kaczmarski, Krzysztof. Rate constants of mass transfer kinetics in reversed phase liquid chromatography. United States. doi:10.1002/aic.10565.
Hong, Lan, Gritti, Fabrice, Guiochon, Georges A, and Kaczmarski, Krzysztof. Thu . "Rate constants of mass transfer kinetics in reversed phase liquid chromatography". United States. doi:10.1002/aic.10565.
@article{osti_989572,
title = {Rate constants of mass transfer kinetics in reversed phase liquid chromatography},
author = {Hong, Lan and Gritti, Fabrice and Guiochon, Georges A and Kaczmarski, Krzysztof},
abstractNote = {The parameters of the kinetics of mass transfer of several n-alkylbenzenes were measured by the method of moments on a series of columns prepared with different samples of the same RPLC packing material having widely different average particle diameters, from 3 to 50 {micro}m. These data were analyzed using the available models, and correlations. The best agreement between experimental and theoretical data was obtained under the assumption that the rate constant for the external mass transfer increases with increasing average particle size, an unexpected conclusion. It was also shown that the interpretation of the relative importance of the roles of pore diffusivity and surface diffusivity in the internal mass transfer kinetics is somewhat ambiguous and that the conclusion to be drawn from experimental results depends on the assumptions made regarding the tortuosity model and the relationship between k{sub ext} and the average particle size.},
doi = {10.1002/aic.10565},
journal = {AIChE Journal},
number = 12,
volume = 51,
place = {United States},
year = {Thu Dec 01 00:00:00 EST 2005},
month = {Thu Dec 01 00:00:00 EST 2005}
}
  • The effect of microwave irradiation on the kinetics of mass transfer in reversed-phase liquid chromatography (RPLC) was studied by measuring its influence on the band profile of propylbenzene in a C{sub 18}-silica column eluted with an aqueous solution of methanol and placed inside a microwave oven. The elution peaks were measured by the pulse-response method, under linear conditions. The amount of microwave energy induced into the column was varied based on the microwave input power. The experimental data were analyzed using the conventional method of moment analysis and the lumped pore diffusion model. With input powers of 15 and 30more » W, the effluent temperatures were 25 {+-} 1 and 30 {+-} 1 C, respectively. The effect of microwave irradiation on the mass transfer of the studied solute was determined by comparing the band profiles obtained under the same experimental conditions, at the same temperature, with and without irradiation. The values of the intraparticle diffusion coefficient, D{sub e}, measured with microwave irradiation were ca. 20% higher than those obtained without irradiation. Derived from the method of moments, the values of D{sub e} at 15 W (25 {+-} 1 C) and 0 W (25 {+-} 1 C) were 8.408 x 10{sup -6} cm{sup 2} s{sup -1} and 6.947 x 10{sup -6} cm{sup 2} s{sup -1}, respectively, while these values at 30 W (30 {+-} 1 C) and 0 W (30 {+-} 1 C) were 9.389 x 10{sup -6} cm{sup 2} s{sup -1} and 7.848 x 10{sup -6} cm{sup 2} s{sup -1}, respectively. The values of the surface diffusivity, D{sub S}, also increased with increasing power of the microwave irradiation. It is assumed that the increase in intraparticle diffusion for propylbenzene was caused by the molecular excitation of the organic modifier that has a higher dielectric loss than the solute. The values of D{sub e} were also analyzed and determined using the POR model. There was an excellent agreement between the results of the two independent methods. These preliminary results suggest that microwave irradiation may have a considerable influence on the mass transfer kinetics in RPLC.« less
  • The thermodynamics and the mass transfer kinetics of the chromatographic system made of phenol, in a water-acetonitrile mobile phase, on a C18 RPLC column, were studied in the temperature range from 21 to 77 C and the interstitial velocity range of 0.021 to 1.27 cm/s. The equilibrium isotherm was accurately approximated by a multilayer model assuming lateral interactions between adsorbed molecules. The parameters of the kinetics of the phenol mass transfer in this column were measured by the method of moments. These data were analyzed using the available models and correlations. It was proven that the parameters of the massmore » transfer kinetics measured under linear conditions could be successfully used for the prediction of the concentration profiles obtained under overloaded conditions.« less
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