Modeling of thermal processes in high pressure liquid chromatography. I. Low pressure onset of thermal heterogeneity

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Journal of Chromatography A

DOI:https://doi.org/10.1016/j.chroma.2009.07.020· OSTI ID:1041462

Kaczmarski, Krzysztof ^[1]; Guiochon, Georges A ^[2]

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1. University of Tennessee and Rzeszow University of Technology, Poland
2. ORNL

Heat due to viscous friction is generated in chromatographic columns. When these columns are operated at high flow rates, under a high inlet pressure, this heat causes the formation of significant axial and radial temperature gradients. Consequently, these columns become heterogeneous and several physico-chemical parameters, including the retention factors and the parameters of the mass transfer kinetics of analytes are no longer constant along and across the columns. A robust modeling of the distributions of the physico-chemical parameters allows the analysis of the impact of the heat generated on column performance. We developed a new model of the coupled heat and mass transfers in chromatographic columns, calculated the axial and radial temperature distributions in a column, and derived the distributions of the viscosity and the density of the mobile phase, hence of the axial and radial mobile phase velocities. The coupling of the mass and the heat balances in chromatographic columns was used to model the migration of a compound band under linear conditions. This process yielded the elution band profiles of analytes, hence the column efficiency under two different sets of experimental conditions: (1) the column is operated under natural convection conditions; (2) the column is dipped in a stream of thermostated fluid. The calculated results show that the column efficiency is remarkably lower in the second than in the first case. The inconvenience of maintaining constant the temperature of the column wall (case 2) is that retention factors and mobile phase velocities vary much more significantly across the column than if the column is kept under natural convection conditions (case 1).

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1041462
• Journal Information: Journal of Chromatography A, Journal Name: Journal of Chromatography A Journal Issue: 38 Vol. 1216; ISSN 0021-9673; ISSN JOCRAM
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
EFFICIENCY
EXTRACTION COLUMNS
FLOW RATE
FRICTION
HEAT TRANSFER
HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY
KINETICS
MASS TRANSFER
NATURAL CONVECTION
PERFORMANCE
RETENTION
SIMULATION
TEMPERATURE DISTRIBUTION
TEMPERATURE GRADIENTS
VISCOSITY