Predictions of overloaded concentration profiles in supercritical fluid chromatography

• Published in: Journal of Chromatography A 2021-02, Vol.1639, p.461926, Article 461926
• Main Authors: Leśko, Marek, Samuelsson, Jörgen, Glenne, Emelie, Kaczmarski, Krzysztof, Fornstedt, Torgny
• Format: Article
• Language: English
• Subjects: Carbon dioxide; Chemistry - Analytical Chemistry; Concentration profiles; Density gradients; Effluent treatment; Gas chromatography; Heat and mass transfer models; Heat balance; Heat balance equations; Kemi - analytisk kemi; Mass balance; Mass transfer; Mobile phase flow rate; Mobile-phase velocity; Overloaded concentration profiles; Radial temperature; Super critical fluid chromatography; Supercritical fluid chromatography; Supercritical fluids; Temperature and pressures; Temperature gradients
• ISSN: 0021-9673; 1873-3778
• DOI: 10.1016/j.chroma.2021.461926

4•Significant temperature and density gradients occur over the columns in UHPSFC.4•Overloaded elution profiles were modeled under non-isopycnic conditions.4•2D heat-mass-balance models were used to correctly predict adsorption processes.4•Radial temperature/density gradients did not influence overloaded elution profiles.4•The equilibrium constant strongly depends on the mobile phase density. Here, overloaded concentration profiles were predicted in supercritical fluid chromatography using a combined two-dimensional heat and mass transfer model. The heat balance equation provided the temperature and pressure profiles inside the column. From this the density, viscosity, and mobile phase velocity profiles in the column were calculated. The adsorption model is here expressed as a function of the density and temperature of the mobile phase. The model system consisted of a Kromasil Diol column packed with 2.2-µm particles (i.e., a UHPSFC column) and the solute was phenol eluted with neat carbon dioxide at three different outlet pressures and five different mobile phase flow rates. The proposed model successfully predicted the eluted concentration profiles in all experimental runs with good agreement even with high-density drops along the column. It could be concluded that the radial temperature and density gradients did not significantly influence the overloaded concentration elution profiles.