Application of helium microwave-induced plasma mass spectrometry to the detection of high ionisation potential gas phase species

Abstract

The determination of fluorine, chlorine, bromine and iodine as positive ions is accomplished using a helium microwave-induced plasma (MIP) as an ion source for quadrupole mass spectrometry. A helium MIP sustained in an internally tuned TM₀₁₀ cavity is interfaced to a commercially available mass spectrometer for the detection of the aforementioned halogens as positive ions. The mass spectral background of the helium MIP and the effect of plasma sampling parameters on the background are discussed. Detection limits for Cl⁺, Br⁺ and l⁺, from the methyl halogens, are estimated to be at picogram levels or lower.