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

Kinetic behaviour in supercritical fluid chromatography with modified mobile phase for 5μm particle size. Part II: Effect of outlet pressure changes

“…As expected in regards of the fluid density, the temperature effects seem reduced at 25 MPa but due to lower diffusion coefficient, higher kinetic performances are reached at 8 MPa, in a temperature range from 20 to 40 • C, for high flow rates (above 5 ml/min). The reported behaviours on the effect of temperature on pressure drop and efficiency are in general accordance with other works [25]. Whatever the outlet pressure, a temperature oven of 20 • C seems to minimise the cooling effect, and can be recommended for flow rates lower than 5 ml/min.…”

Possibilities of retention modeling and computer assisted method development in supercritical fluid chromatography

“…The interconversion between isocratic and gradient retention data was found to be less straightforward than in RPLC and HILIC. This behavior is in agreement with our expectations since the pressure generated by the column may vary between the different isocratic and gradient conditions (different mobile phase viscosity, depending on the percentage of methanol) [2,26,27]. Considering that in SFC, pressure has a very strong impact on the mobile phase density and its eluent strength, the inevitable change in experienced pressure between an isocratic and a gradient run severely compromises retention prediction in SFC.…”

Instrumentation for analytical scale supercritical fluid chromatography

“…Recent reports [6,7] make it clear that, particularly with sub-2 m particles, the mobile phase can either warm or cool, depending on composition, during decompression along the column. Axial temperature gradients do not affect efficiency.…”

“…A number of articles (see [6,7]) have recently appeared regarding axial and radial temperature gradients that form when CO 2 decompresses across the column pressure drop. With pure CO 2 , the decompression results in extensive cooling [6]. With modified fluids, there may be either cooling or warming [7], depending on composition.…”