Spot testing

Karin Abelskamp <k.abelskamp [at] archeologie__nl>

>I am looking for a spot test to demonstrate the presence of tin in
>an archaeological object made of a copper alloy object or a lead
>alloy. Does anyone know if such a test is commercially available? If
>so, where can I purchase it, preferably in the Netherlands?
>Furthermore, is such a test perhaps also available for zinc?

The book "Material Characterization Tests for Objects of Art and
Archaeology" by Odegaard, Carroll, and Zimmt (2000, Archetype
Publications) have several qualitative tests for both zinc and tin,
however, some of the necessary reagents are hard to find.  I have
discovered that the Merck EMD Quant Tin Test (#10028-1) and Zinc
Test (#10038-1) (available through Fisher Scientific, and probably
other suppliers) can be adapted to suit the purpose.  These are "dip
strip" type tests for semi-quantitative measurements of ions in
solution, but they can also be used for qualitative ID.  If you can
liberate a few ions from the surface of your objects using the
filter paper spot-test techniques in Odegaard et al, and then dilute
that in enough solution to wet the test strip, Viola!  We have
successfully tested this to ID zinc in brass and tin in bronze.

Merck has additional information on the tests at
<URL:http://fea.merck.de/>

Howard Wellman
Maryland Archaeological Conservation Laboratory
410-586-8577


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                  Conservation DistList Instance 19:23
                 Distributed: Friday, October 28, 2005
                       Message Id: cdl-19-23-007
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