Methylene selectivity and eluotropic strength variations in subcritical fluid chromatography with packed columns and CO2-modifier mobile phases

This work has consisted of better understanding the chromatographic behavio r in subcritical fluid chromatography with CO2-acetonitrile and CO2-methano l mobile phases. To that end, the changes of solute solubility in the mobil e phase have been studied by determination of methylene selectivity of a ho mologous series. Moreover, eluotropic strengths have been calculated for mo bile phases containing from 5 to 45% modifier. To carry out the studies in all ranges of the subcritical area, experimental designs have been used. Th e influences of analytical temperature (from 10 to 30 degrees C) and outlet pressure (from 10 to 20 MPa) have also been investigated both on solubilit y and on eluotropic strength. A more general comparison of eluotropic stren gths of subFC and HPLC has been achieved.