Direct heated interface probe for capillary supercritical fluid chromatography/double focusing mass spectrometry

A capillary supercritical fluid chromatograph was occupied to a double focusing mass spectrometer with a direct heated probe interface. The interface contained a fused silica transfer capillary containing a frit restrictor at the end which was heated to a temperature of 300-350/degrees/C by resistance heating. The total column effluent was transferred into the mass spectrometer ion source. This interface not only preserved the chromatographic efficiency but also provided for mass spectral detection and identification of various high molecular weight, thermally labile, and polar compounds. Electron-impact and chemical ionization mass spectra of selected natural products and pharmaceuticals were obtained at the low nanogram level.