Comparison of Ar and Ne as working gases in analytical glow discharge mass spectrometry

Summary

Glow discharge mass spectrometry shows promising analytical performance, in particular low detection limits. Its application is impeded by problems with molecular interferences, a major group of which is made up by argides. Problems of this type can be eliminated effectively by use of alternative working gases. Investigations have been made concerning the application of Ne as alternative working gas in comparison with the commonly used Ar. Differences in spectral interferences are discussed with the example of spectra of a very pure Fe standard sample. Influence of pressure and power variation on elemental sensitivities and analytical figures of merit has been studied. Nearly equal values of the electrical parameters with similar analytical performance can be realized with both gases if a correspondingly lower pressure is chosen for Ar. Pressure dependence enables two different analytical operation modes: one to give highest detection power and precision, and the other to give better accuracy in case of a semiquantitative analysis which does not require standards or knowledge of sensitivity factors.