Ion-mobility spectrometry as a detection method for packed-column supercritical fluid chromatography

Abstract

Initial investigations are reported for the use of an ion-mobility spectrometer as a detector for packed-column supercritical fluid chromatography. The spectrometer was coupled to the supercritical fluid chromatography system throug a post-column split, and a small portion of the chromatographic flow was introduced directly into the ion-mobility spectrometer using either a frit restrictor or an integral restrictor. The effect of a mobile phase modifier, methanol, on the gas phase ion chemistry of the detector was studied using the reactant ions normally present in the drift tube and the response of the detector to benzoquinone and benzophenone. Separations were performed for a series of Triton X oligomers to demonstrate the various operational modes of the detector. Product ions captured for these compounds had reduced mobilities, a dimensionless measure of mobility, in the range of 1.00 to 0.405, which would make these some of the largest compounds ever introduced, individually, into an ion-mobility spectrometer.