Abstract: An analytical instrument using a plasma is disclosed. The instrument includes two plasma torches, a first torch of which is used for vaporizing a sample and a second plasma torch is used for exciting the sample. When the analytical instrument is a mass spectrometer, the sample vaporized by the first plasma torch is introduced into the second plasma torch where the sample is ionized. The sample is then mass analyzed. If the sample is a small solid sample, it is momentarily vaporized by the plasma flame generated from the first plasma torch. If the sample is a large solid sample, it can be gradually vaporized from its surface. Therefore, the sample can be analyzed without requiring any pretreatment, e.g., dissolving the sample in an acid.

Abstract: An ion source for use in a mass spectrometer comprises a porous member arranged in the ionization chamber and bearing against the inlet tube so as to obstruct the open end of the inlet tube. A particle beam is directed to the effluent which exudes from the surface of the porous member after passing through the porous member. A cover shields a portion of the surface of the porous member from the particle beam so as only the most recently exuded effluent is irradiated. The effluent supplied into the porous member by the inlet tube is allowed to exude from surfaces of the porous member other than the surface bombarded with the particle beam so as to carry away stale effluents.