| 초록 |
The effects of temperature and pressure on retention of azulene and acenaphthylenein supercritical fluid chromatography are investigated within 33 to 58 C and 74 to150 bar. The capacity factors are used to derive the infinite-dilution partial molarvolumes of the two solutes in supercritical carbon dioxide, and infinite-dilution molarenthalpies of transfer of azulene from the stationary phase to supercritical CO2. Thepartial molar volumes are converted to quantities characterizing short-range interactionsbetween CO2 and the aromatic hydrocarbon. The results obtained by analyzing theretention data in the usual way are compared with a more refined treatment thattakes account of the pressure- and temperature-dependent dissolution of CO2 inthe stationary polymer (PDMS) within the column. The corrections for compositionchanges in the stationary phase employ a combination of the Flory-Huggins theory,the regular solution theory, and the Panayiotou-Vera lattice-fluid model. Applicationof the composition correction makes the partial molar volumes and the transferenthalpies more negative. The composition correction may help to reconcile thedisparity between the chromatographic and the solubility values of partial molarvolumes.
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