(189r) Influence of the Equations of State On the Characterization of Supercritical Fluid Chromatographic Systems

Chromatography is an adsorption separation technique, which exploits the relative affinity of different molecules towards stationary phases, like porous solids, membranes, even liquid. It plays a crucial role in bio-pharmaceutical, chiral, fine chemical, food & beverages, and many other industries. The main strength of this technique is its ability to separate almost any complex mixture with great precision. The problems, on the other hand, are its low productivity, high cost of chromatographic materials and usage of a significant volume of solvents, which threaten its future sustainability.

Supercritical fluid chromatography (SFC), which mainly uses supercritical carbon-dioxide as the mobile phase along with other additives, is emerging as the sustainable variety of chromatographic processes. The primary problem in a widespread use of SFC is its complexity and lack of proper physical understanding in designing competitive industrial processes. To achieve this, one needs to write reliable mathematical models for in-depth analysis. The selection of the equations of state (EOS) is one of the most important issues in this direction, because the retention behavior in SFC is strongly related to the density of the mobile phase, which is provided by the EOS as a function of the directly measurable temperature and pressure. Several EOS with varied accuracy and computational loads, like Lee-Kessler, Span-Wagner etc., have been used in this direction. A comparative study among their specific applicability, however, is still pending. The presentation will compare the influence of different EOS on the retention behavior and chromatographic profiles, and will demonstrate the applicability of these EOS according to the precision demand.