Abstract by Callum Flowerday
Chemistry and Biochemistry
Thermal Gradient Application in Solvating Gas Chromatography
Supercritical fluids can be used as mobile phases for supercritical fluid chromatography (SFC). CO2 is a common choice of fluid. Usually, a flow restrictor is placed at the end of the column to maintain the pressure across the column so that the CO2 remains supercritical. By contrast, in solvating gas chromatography (SGC), no restrictor is used, which leads to a large pressure gradient and allows the mobile phase to become more gas-like as the pressure drops across the column. The analytes become less soluble in the mobile phase as the mobile phase becomes more gas-like, which causes a band focusing effect leading to narrow bands in the column. However, although analytes travel quickly through the first part of the column, at the end of the column, they move slowly, causing them to appear as broad bands as they are detected. We are investigating the application of a thermal gradient along the column, thereby decreasing elution time without losing resolution with the increase in column temperature at the end of the column offsetting the lower solvating power of the mobile phase.