Effects of methane addition to nebulizer gas on polyatomic interferents and ion sensitivity in inductively coupled plasma mass spectrometry

First published online 09 Oct 2013The addition of methane to nebulizer gas was assessed as a method for the reduction of polyatomic interferents in inductively coupled plasma mass spectrometry (ICP-MS). The effects of nebulizer gas flow rate, RF power and methane flow were studied for a range of analytes and polyatomic ions. The analyte sensitivity, especially for Be, Br and I, was enhanced by a factor of 7–12 with methane addition. Polyatomic ions, such as ArCl+, ArO+, ClO+ and ArArH+, were reduced between 61 and 92% when compared to those of an unmodified plasma. Such reduction allowed better quantification limits for V, As, Se, Br and I, as well as 90% BaO+ polyatomic reduction. Finally, the optimized conditions were evaluated in successful recovery tests for As, Se and V in different matrices with high chloride content. The Fe accuracy was evaluated in several reference materials