A method of operating an inductively coupled plasma mass spectrometry apparatus for analyzing an analyte sample, the mass spectrometry apparatus including a plasma ion source, a mass analyzer and an interface arrangement positioned between the plasma ion source and the mass analyzer of the mass spectrometer, the interface arrangement at least including an interface structure, including a sampling or skimmer cone, and at least one passage with an inlet and an outlet into a reaction zone, the method including: generating a plasma using the plasma ion source and forming a plasma flux to flow towards the mass analyzer; supplying the analyte sample into the reaction zone via the passage such that the analyte sample interacts with the plasma flux; and analyzing the analyte sample using the mass analyzer.