DEVELOPMENT AND APPLICATION OF PACKED-COLUMN SUPERCRITICAL-FLUID CHROMATOGRAPHY PNEUMATICALLY ASSISTED ELECTROSPRAY MASS-SPECTROMETRY

A pneumatically assisted electrospray liquid chromatography/mass spect rometry (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 chroma tographic fidelity was preserved using a novel pressure-regulation sch eme. Post-column pressure regulation was accomplished by adding a ''pr essure-regulating fluid'' (supplied under pressure control) to the eff luent just ahead of the sprayer. The modified interface has been used to characterize a variety of mixtures including emollients, modified p olysiloxanes, 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.