Temperature and pressure effects on solubility in supercritical carbon dioxide and retention in supercritical fluid chromatography

Solubilities of some polycyclic aromatic hydrocarbons (PAHs) in supercritical carbon dioxide were measured with a procedure based on a direct on-line combination of a saturation cell to a flame ionization detector. Acenaphthene, anthrance and chrysene were selected as the test solutes. A method was developed and evaluated which enables the measurement of the contribution of solute vapor pressure to the overall solubility. The effects of temperature and pressure on solubility in supercritical carbon dioxide were investigated and discussed in detail. The trends of solubility changes in supercritical carbon dioxide and the variations in observed retention in supercritical fluid chromatography (SFC) were correlated. Equations were derived to estimate the effects of temperature on the solute's affinity for the stationary phase in SFC.