[NHCOLL-L:1496] arsenic - false positives?

[Bob Glotzhober]

In the last 2 or 3 years I've done about 250 tests of mounted animals for
arsenic -- using the guidelines with the Merck test kits and more recently
some refinements from the Smithsonian folks.

Today I had a group of recently donated mounts -- all of recent origin --
but to be certain since some are to be used in loan boxes, I ran arsenic
tests on them.  All came up clear, except for one raccoon, which came out
about halfway between 0.1 and 0.5 on their color scale.  It did not make
sense that this animal had arsenic in it, so I re-tested it, and it came out
0.0.  Anyone else every have any experience with false positive tests?
Makes me wonder if any of the specimens we pulled from loan kits were
actually OK after-all.  Does anyone routinely run 2 or more tests per
animal?  I cannot explain the false (?) positive -- and that disturbs me.
Any insights would be appreciated.

Bob


> ===========================================
> Robert C. Glotzhober		bglotzhober at ohiohistory.org
> Curator of Natural History		phone  614 297-2633
> Ohio Historical Society		fax       614 297-2233
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