Interested to know what would cause such a disparity in I.S recoveries between tune modes. In this example, Germanium and Tellurium trace is relatively stable in the High energy helium tune (8 mL/min) though same Ge, Te acquired in standard He mode (5 mL/min) including other I.S, are trending down. I have seen downward trends before from unconditioned cone but why would HEHe trace show better stability when acquired from the same sample. Trace collected after a cone clean and condition. Method is running serum, 3 tunes modes of 3ml/min to 5ml/min to 8ml/min with 5 sec stabilisation time between. Agilent 7900 ICP-MS.