Separation of perfluorinated polyethers using packed capillary column supercritical fluid chromatography

Newly developed perfluorinated polyethers, HOCH2O[(CF2O)(p)(CF2CF2O)(q)]CH2 OH (Z-Dols), were separated using packed capillary column supercritical flu id chromatography (SFC). A fluorocarbon-bonded stationary phase, Fluofix 12 0N (5 mu m and 120 Angstrom), was used as a packing material and the perfor mance of this stationary phase was investigated under different experimenta l conditions. The effects of column length, pressure, and temperature on se paration were studied. Approximately 180 oligomers of perfluorinated polyet hers with an average molecular weight range from 2000 to 4000 were well res olved using an 85 cm x 200 mu m i.d. column at 110 degrees C under pressure programming conditions. The chromatographic behavior of the fluorocarbon-b onded. stationary phase was compared with octadecyl silica (ODS) particles under SFC conditions. The results show Fluofix 120N has more selective rete ntion than ODS for perfluorinated polyethers. The effects of Freon F-113, m ethanol, and water as sample solvent on stationary phase stability were als o examined. It was found that the column efficiency with the Fluofix 120N s tationary phase did not deteriorate significantly using Freon and methanol as sample solvents but decreased by 30% using water at 110 degrees C for 48 h. (C) 1999 John Wiley & Sons, Inc.