Abstract: An improved ionization source for a mass spectrometer is constructed of a subsurface of metal that has a smooth surface obtained by, for example, electropolishing, and an inert surface thin enough to have a surface finish opposing the subsurface that replicates that of the subsurface. Preferably the inert surface has a thickness that is less than 0.001 inches and is gold. Operation of a mass spectrometer with the improved ionization source results in reduced adsorption and reduced reactions between charged molecules or ions and metallic surfaces. Micro-machining of the subsurface metal before electropolishing enhances smoothness and decreases resulting debris collection on the improved ionization source. The improved ionization source remains serviceable for longer periods and is easier to clean and recondition for continued use as compared to known mass spectrometer ionization sources.

Abstract: An improved ionization source for a mass spectrometer is constructed of stainless steel, electropolished, and electroplated with gold. Operation of a mass spectrometer with the improved ionization source results in reduced adsorption and reduced reactions between charged molecules or ions and metallic surfaces. Micro-machining before electropolishing enhances smoothness, brightness, passivation and inertness of the improved ionization source. Use of the electropolished, gold-electroplated stainless steel ionization source in a mass spectrometer reduces adsorption, degradation and decomposition of the analyte and reduces adverse ion/surface reactions, as compared to use of a conventional stainless steel ionization source. A method of reducing adsorption, degradation and decomposition of the analyte and reducing adverse ion/surface reactions in an ionization source containing an electropolished and gold-electroplated ionization source for a mass spectrometer is also disclosed.