Effect of organic solvents and molecular gases on polyatomic ion interferences in inductively coupled plasma mass spectrometry

Abstract

The introduction of an organic solvent (ca. 10% propan-2-ol in water) or a molecular gas (<5% O₂ or N₂) into the central channel of the inductively coupled plasma has been shown to cause dramatic reductions in signals due to the polyatomic ions ArCl⁺, ArAr⁺ and ClCl⁺, with corresponding increases in the In⁺ : XY⁺ ratios using inductively coupled plasma mass spectrometry (ICP-MS). Some evidence for the competitive formation of species such as ArC⁺, ArN⁺ and ArO⁺, or CCl⁺, NCl⁺ and OCl⁺ in preference to the other interfering ions, was observed, depending on the method employed. The use of N₂ at a flow-rate of 0.03 l min^–1 doped into the central channel is recommended for the minimisation of ArCl⁺ interference in analysis by ICP-MS.