Evaluation of co-solvent fraction, pressure and temperature effects in analytical and preparative supercritical fluid chromatography

• Combined effect of temperature, pressure and methanol fraction is studied in SFC.
• Design of experiments and careful measurement of input parameters are used.
• Methanol fraction was most important for retention, selectivity and productivity.
• Pressure was mainly affecting the retention, but not selectivity and productivity.
• Temperature was only important for selectivity and productivity.

A chemometric approach is used for studying the combined effect of temperature, pressure and co-solvent fraction in analytical and preparative supercritical fluid chromatography (SFC). More specifically, by utilizing design of experiments coupled with careful measurements of the experimental conditions the interaction between pressure, temperature and co-solvent fraction was studied with respect to productivity, selectivity and retention in chiral SFC. A tris-(3,5-dimethylphenyl) carbamoyl cellulose stationary phase with carbon dioxide/methanol as mobile phase and the two racemic analytes trans-stilbene oxide (TSO) and 1,1′-bi-2-naphthol (BINOL) were investigated. It was found for the investigated model system that the co-solvent fraction and pressure were the parameters that most affected the retention factors and that the co-solvent fraction and column temperature were most important for controlling the selectivity. The productivity in the preparative mode of SFC was most influenced by the co-solvent fraction and temperature. Both high co-solvent fraction and temperature gave maximum productivity in the studied design space.