Ion sources for analysis of inorganic solids and liquids by MS

Inorganic mass spectroscopy (MS) has moved out of the realm of very specialized and expensive science in the past several years and is beginning to take hold in many more industrial, environmental, medical and university labs. The development and commercialization of ion sources that accommodate solid and liquid samples, and their adaptation to various mass spectrometers, are largely responsible for this expansion. The multielement capabilities of the glow discharge (GD) and the inductively coupled plasma (ICP) have been combined with quadrupole mass filters to make relatively inexpensive, versatile instruments for elemental analysis that are beginning to replace traditional spectroscopic methods. At the same time, detection limits are continually being lowered and spatial resolution improved in secondary ion mass spectroscopy (SIMS), allowing smaller and smaller samples to be mass analyzed. Because these ion sources are readily available with different types of mass analyzers, the analyst can balance the merits of various combinations of precision, analysis time, and cost. Recent trends are toward commercial availability of adaptable mass spectrometers, where GD and ICP sources may be interchanged, or thermal or secondary ionization may be used. 46 refs., 2 figs., 1 tab.