Efficiency for unretained solutes in packed column supercritical fluid chromatography II. Experimental results for elution of methane using large pressure drops.
At near-critical temperatures and pressures, experimental results for elution of methane with neat carbon dioxide on a 150 mm x 2.0 mm I.D. column packed with 5 microm porous silica with a bonded octylsilica stationary phase show much greater efficiency losses than predicted by theory if isothermal conditions are assumed. Experiments with insulated, air- and water-thermostatted columns demonstrate that significant axial and radial temperature gradients are produced by Joule-Thomson cooling of the mobile phase, and that radial temperature gradients can be a major cause of band spreading at low temperatures and pressures. The use of thermal insulation on the column can greatly improve efficiency under these conditions.
Xu
Wensheng
W
Department of Chemistry, University of Minnesota Duluth, 10 University Drive, Duluth, MN 55812, USA.
Peterson
Dawn L
DL
Schroden
Jonathan J
JJ
Poe
Donald P
DP
D002245:Carbon Dioxide / Q000737:chemistry; D002853:Chromatography, Liquid / Q000379:methods*; D008697:Methane / Q000302:isolation & purification*; D011312:Pressure; D013696:Temperature
D002245:Carbon Dioxide; D008697:Methane