title: Pressure, temperature and density drops along supercritical fluid chromatography columns in different thermal environments. III. Mixtures of carbon dioxide and methanol as the mobile phase.
abstract: The pressure, temperature and density drops along SFC columns eluted with a CO2/methanol mobile phase were measured and compared with theoretical values. For columns packed with 3- and 5-μm particles the pressure and temperature drops were measured using a mobile phase of 95% CO2 and 5% methanol at a flow rate of 5mL/min, at temperatures from 20 to 100°C, and outlet pressures from 80 to 300bar. The density drop was calculated based on the temperature and pressure at the column inlet and outlet. The columns were suspended in a circulating air bath, either bare or covered with foam insulation. The experimental measurements were compared to theoretical results obtained by numerical simulation. For the convective air condition at outlet pressures above 100bar the average difference between the experimental and calculated temperature drops and pressure drops were 0.1°C and 0.7% for the bare 3-μm column, respectively, and were 0.6°C and 4.1% for the insulated column. The observed temperature drops for the insulated columns are consistent with those predicted by the Joule-Thomson coefficients for isenthalpic expansion. The dependence of the temperature and the pressure drops on the Joule-Thomson coefficient and kinematic viscosity are described for carbon dioxide mobile phases containing up to 20% methanol.
authors: Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN 55812 USA. Electronic address: dpoe@d.umn.edu.
authors: Donald P
authors: DP
authors: Poe
authors: Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN 55812 USA.
authors: Devon
authors: D
authors: Veit
authors: Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN 55812 USA.
authors: Megan
authors: M
authors: Ranger
authors: Department of Chemical and Process Engineering, Rzeszow University of Technology, 35-959 Rzeszow, Poland.
authors: Krzysztof
authors: K
authors: Kaczmarski
authors: Waters Corporation, Milford, MA, USA.
authors: Abhijit
authors: A
authors: Tarafder
authors: Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600, USA; Division of Chemical Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
authors: Georges
authors: G
authors: Guiochon
mesh_terms: D000388:Air; D001696:Biomechanical Phenomena; D002245:Carbon Dioxide / Q000737:chemistry*; D025924:Chromatography, Supercritical Fluid / Q000379:methods*; D000432:Methanol / Q000737:chemistry*; D008962:Models, Theoretical; D011312:Pressure; D013696:Temperature; D013816:Thermodynamics; D035501:Uncertainty; D014783:Viscosity
chemical_list: D002245:Carbon Dioxide; D000432:Methanol
keywords: Density drop; Isenthalpic expansion; Pressure drop; SFC; Supercritical fluid chromatography; Temperature drop