FACTORS AFFECTING THE PREPARATION OF PACKED CAPILLARY COLUMNS IN SUPERCRITICAL CARBON-DIOXIDE MEDIA

In this study, packed capillary columns were prepared using supercriti cal carbon dioxide as a packing carrier. A factorial design was used t o examine the effect that four selected factors have on the packing pe rformance. The investigated factors were: 1) packing pressure, 2) carb on dioxide flow rate, 3) presence of a pressure ramp, and 4) sonicatio n power. The performance of the columns (in terms of reduced plate hei ght) was evaluated using a liquid chromatograph. The model obtained in dicated that the best packing conditions would be high pressure, long restrictor, and use of a pressure ramp. Sonication was found to be nec essary, although no significant difference in packing performance was detected between the sonication power settings evaluated in this study . An attempt is made to explain the effect of the studied factors on t he packing process. (C) 1997 John Wiley & Sons, Inc.