Numerical modeling of elution peak profiles in supercritical fluid chromatography. Part I-Elution of an unretained tracer

Journal Article · Fri Jan 01 00:00:00 EST 2010 · Journal of Chromatography A

DOI:https://doi.org/10.1016/j.chroma.2010.08.035· OSTI ID:1041474

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

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

When chromatography is carried out with high-density carbon dioxide as the main component of the mobile phase (a method generally known as 'supercritical fluid chromatography' or SFC), the required pressure gradient along the column is moderate. However, this mobile phase is highly compressible and, under certain experimental conditions, its density may decrease significantly along the column. Such an expansion absorbs heat, cooling the column, which absorbs heat from the outside. The resulting heat transfer causes the formation of axial and radial gradients of temperature that may become large under certain conditions. Due to these gradients, the mobile phase velocity and most physico-chemical parameters of the system (viscosity, diffusion coefficients, etc.) are no longer constant throughout the column, resulting in a loss of column efficiency, even at low flow rates. At high flow rates and in serious cases, systematic variations of the retention factors and the separation factors with increasing flow rates and important deformations of the elution profiles of all sample components may occur. The model previously used to account satisfactorily for the effects of the viscous friction heating of the mobile phase in HPLC is adapted here to account for the expansion cooling of the mobile phase in SFC and is applied to the modeling of the elution peak profiles of an unretained compound in SFC. The numerical solution of the combined heat and mass balance equations provides temperature and pressure profiles inside the column, and values of the retention time and efficiency for elution of this unretained compound that are in excellent agreement with independent experimental data.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1041474
• Journal Information: Journal of Chromatography A, Vol. 1217, Issue 42; ISSN 0021-9673
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CARBON DIOXIDE
CHROMATOGRAPHY
DIFFUSION
EFFICIENCY
FLOW RATE
FRICTION
HEAT TRANSFER
HEATING
HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY
MASS BALANCE
NUMERICAL SOLUTION
PHASE VELOCITY
PRESSURE GRADIENTS
RETENTION
SUPERCRITICAL FLUID CHROMATOGRAPHY
VISCOSITY