Abstract: A discharge ionization source, for use for example with an ion mobility spectrometer or atmospheric pressure ionization mass spectrometry. The source uses two or more electrodes for ionization and control, and solid state circuitry for operation. Inductive coupling of the discharge gap to the electronics is not necessary. The source can be operated as a continuous dc discharge, or as a pulsed discharge. The two-electrode configuration provides an anode and cathode with an optional adjustable gap. One of the electrodes can be hollow to enhance ionization efficiency (e.g., hollow cathode) and/or to accept effluent from a gas or liquid (including electrophoresis) chromatographic column. The three-electrode configuration adds a third or control electrode to additionally stabilize the discharge. The third electrode may be biased at the potential of the anode through a ballast resistor, and be located near the cathode.

Abstract: An apparatus and method to separate and store ions by exploiting mobility characteristics of the ions. A sample is introduced into a trap volume and ionized. The ions are separated according to their mobility characteristics by applying an electric field to the trap volume. The ions thus migrate to equilibrium positions in the trap volume due to a difference in mobilities and to changes in the electric field. The ions may be sequentially scanned from the trap by changing the electric field. The identity of ions within the trap may then be determined.