Study of molecular interferences in glow discharge mass spectrometry

Abstract

The existence of spectral interferences in glow discharge mass spectrometry (GDMS) limits the use of the technique, a problem which previous efforts have not fully addressed. The standard approaches of selecting an alternative isotope for the analysis or of employing high-resolution instrumentation are seen to be limited in their utility. Investigations aimed at directly preventing the formation of molecular interferences proved successful when precursors could be eliminated. For those species formed from the reaction of discharge gas atoms with sputtered atoms, both of which are essential to the analysis, only a reduction of polyatomic ion populations was achieved by altering discharge conditions. The utilisation of a collision cell between the ion source and the mass analyser gave atomic mass spectra free from polyatomic species, while decreasing the sensitivity only slightly.