these are not Superfund levels by any means (assuming you are seeing no radioactive isotopes), they are actually pretty low. Sr and Ba are very common elements in tap water and ground water. Safe drinking water standards are about 4000 ppb for Sr and 700 ppb for Ba. Any reason to trust your ICP-OES results more than the ICP-MS (especially since you are getting consistent results from multiple isotopes)? It's detection limit should be significantly lower.
"[...] more than half the banana genome is shared with humans (a fact more
evident among some of my acquaintances than others)" - Sir Robert May
Dr. Johan Schijf
Assistant Professor, Aquatic Environmental Geochemistry
UMCES/Chesapeake Biological Laboratory
P.O. Box 38, 1 Williams Street
Solomons, MD 20688-0038
Tel. (410) 326-7387 (office) 7392 (lab)
Fax (410) 326-7341
e-mail: [log in to unmask] Michael Murphy <[log in to unmask]>:
> Dear All,
> 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.
> Michael Murphy
> Research Scientist
> Intertek USA, Inc., d/b/a QTI
> PO Box 470
> 291 rt. 22 East
> Salem Industrial Park, Bldg. 5
> Whitehouse, NJ 08888
> Please note that all comments are my personal opinion and do not
> represent the position of my company.