Development and application of packed-column supercritical fluid chromatography pneumatically assisted electrospray mass spectrometry

A pneumatically assisted electrospray liquid chromatography/mass spectrometry (LC/MS) interface has been modified for use with packed-column supercritical fluid chromatography (pcSFC). The modifications include the addition of a concentric sheath-flow liquid to the spray device. This allowed the addition of modifiers at the sprayer tip that promote ionization of neutral, pcSFC-separated components. Post-column chromatographic fidelity was preserved using a novel pressure-regulation scheme. Post-column pressure regulation was accomplished by adding a "pressure-regulating fluid" (supplied under pressure control) to the effluent just ahead of the sprayer. The modified interface has been used to characterize a variety of mixtures including emollients, modified polysiloxanes, and pharmaceutical agents. The spectra produced by using this pcSFC/MS interface are similar to electrospray LC/MS spectra. (C) 1998 American Society for Mass Spectrometry.