Abstract: An apparatus for providing an ion vapor to be analyzed. A vaporizer probe, with a capillary tube extending into a vapor port of an ion source, has a release end which ejects a spray of vapor into a spray region of the ion source. Molecules of interest within the vapor may be ions pre-formed in solution or may be ionized by chemical ionization or plasma discharge ionization. A minor portion of the vapor is extracted from the spray chamber for mass analysis. The major portion is coaxially redirected from the spray chamber for return to the same port which receives the capillary tube of the vapor probe. A return tube is vacuum sealed to the port and is in fluid communication with a roughing pump which draws the ion vapor from the spray region through the ion source and the port for coaxial vapor backflow with the capillary tube. The ion source has a split-block structure for ease of both manufacture and routine maintenance.

Abstract: A multimode ionization source includes a resistive filament aligned with an exit cone orifice. The filament generates electrons that bombard molecules near the orifice. In electron impact mode, a pressure regulator selects a low pressure within an ionization chamber and gaseous analyte is injected through a gas inlet and ionized by electron bombardment. In chemical ionization mode, an intermediate pressure of reagent gas established; electrons ionize the reagent gas. Gaseous analyte is introduced is ionized by the reagent gas through chemical interaction. In thermospray mode, a high pressure is established and heated liquid analyte is introduced into the chamber as a spray which is ionized by ion evaporation; in a thermospray/chemical ionization submode, filament activation supplements ion evaporation. Ions produced in all modes can be directed to a mass analyzer for analysis.

Abstract: A capillary-direct interface, suitable for connecting a gas chromatograph to a mass spectrometer, having a flow restrictor that is to be mounted at the entrance to the ionization chamber of the mass spectrometer to prevent damage to the mass spectrometer if the column of the gas chromatograph is removed from the mass spectrometer or breaks inside the interface. A preferred flow restrictor includes a hollow tube, the middle of which is connected to an exhaust port to enable a vacuum pump to remove gas from the middle of the tube. The hollow tube is enclosed by a high thermal conductivity tube that is thermally connected to a heat source to control the temperature of the hollow tube. A capillary GC column can be inserted entirely through the hollow tube into the ionization chamber to produce a capillary direct mode of coupling.