CAPILLARY COLUMN SUPERCRITICAL-FLUID CHROMATOGRAPHY MASS-SPECTROMETRY OF POLYCYCLIC AROMATIC-COMPOUNDS USING ATMOSPHERIC-PRESSURE CHEMICAL-IONIZATION

Capillary column supercritical fluid chromatography (SCF) was combined with atmospheric pressure chemical ionization (APCI) mass spectrometry through a heated pneumatic-nebulizer interface, originally developed for liquid chromatography/mass spectrometry (LC/MS), and subsequently modified for use with supercritical fluid chromatography/mass spectrometry (SFC/MS). A high pressure syringe pump was used to pass SFC-grade carbon dioxide, used as the mobile phase, through a capillary SFC column which was contained in an oven, maintained at 100-degrees-C. The eluent passed through the heated pneumatic-nebulizer interface into the ionization region of the mass spectrometer with the aid of the flow of nebulizing gas. The system was optimized using benz[a]anthracene, and then applied to analyze a standard mixture of polycyclic aromatic compounds (PACs) as well as complex mixtures of PACs obtained by the fractionation of a pond sediment contaminated by coke-oven residues. A detection limit of 40 pg was established for chrysene.