Once again the dunce cap is on and I return to the classroom (virtual in this case). While setting up a new ICPMS instrument a "random" sample of tap water (this is well water) was analyzed and showed strong values and nice peaks for barium and strontium. This holds for Ba at mass 137 and 138 and for Sr at mass 88 and 86 in no-gas mode, H2 mode, and He mode. "Apparent" concentration is ~ 2300 ppb Sr and ~90 ppb Ba (the concentration for each analyte is the same at both masses).
This was confirmed on a second ICPMS (no cell installed) but, fortunately, the ICPOES did not see Ba or Sr.
Relieved as I am that I am not working overtop a future Superfund site I admit that I cannot see what species are causing these rather consistent readings (e.g. Ba138 = 607596 counts = 89.9 ppb, Ba 138 = 3874062 counts = 90.2 ppb, Sr 88 = 94962677 counts = 2390 ppb and Sr 86 = 10714443 counts = 2320 ppb). If it is a polyatomic problem I cannot find a structure(s) that make sense.
I am assuming that some of you know these interferences by heart, so any insight would be much appreciated.
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Please note that all comments are my personal opinion and do not represent the position of my company.