Resolution/Axis troubleshooting & He mode drift

Hi everyone,

Recently, when we've been running the warm up procedure on our ICP-MS 7900, an error message appears next to Resolution/Axis.
It says that there is a potential interfering peak at m/z 6. We've cleaning every part possible (cones, lenses, torch etc) and changed tubing but still have no luck in getting rid of this. Could there be possible contamination somewhere or has anyone had this error message before and knows what it could mean?  We monitor masses 7, 89 and 205 during the start-up.


In addition to this, we've also been experiencing significant fluctuation/drift in analysis for He mode. Randomly in the middle of a batch, any elements and ISTD analysed under He mode drops in recovery significantly, then when I rerun the same sample immediately after, recovery comes back into spec and results are acceptable. Turning off the internal standard makes no difference to the results, so I don't think that's the issue. This is even happening with relatively easy/low matrix samples such as our rinses and QC samples. Anyone any advice on where to go from here or what's causing this disruption?

Thanks in advance
Taylor

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