Method and device for elemental analysis of a sample by mass spectrometry coupled to a high frequency induced plasma.

摘要

Improvement to the method of elemental analysis of a sample by mass spectrometry coupled to a plasma induced by high frequency, by means of an installation including a torch for producing the plasma from a plasma-forming medium and for injecting some of the sample into this plasma and a sample-withdrawal interface, comprising two successive cones arranged on the same axis but having different vertex angles and each provided with an axial orifice for the passage of a fraction of the sample to be analysed. According to the invention, a given quantity of a make-up gas, with high calorific value, is added to the sample injected into the plasma, in such a way as to raise the temperature of the plasma in order to locally heat the withdrawal cones so as to preclude the deposition on the latter of the components of the sample which are present in the plasma. Preferably, the withdrawal cones (18, 19) are made from an alloy of niobium, hafnium, titanium. <IMAGE>