There has been a long history of ceramic trace element analysis in this
department, although it is not my particular field of study. Much of
the work carried out in the 80s and early 90s involved XRF or INAA, but
there have also been various AAS and ICP-AES studies for which the
sample prep will be basically the same as for ICP-MS. I think the
methods vary a bit but are usually based on hydrofluoric and perchloric
acid digestions. The following is typical:-
1. Remove the sherd surface layer with a drill using a tungsten-carbide
burr and then either use the burr to obtain a powder sample or chip a
sample off (typically ~0.1 - 0.5g) and ball mill (or agate pestle and
mortar and elbow power) it to a powder. It's then usually sieved. (I
think this is to remove large mineral temper inclusions thought not to
be representative of the clay matrix). The powder is then usually dried
at ~100oC overnight or longer.
2. The sample is placed in a teflon beaker with the acids. The paper I
have here says 0.25g of powdered sample to 10ml HF (40%) and 3ml HClO4
(70%). The beaker is then placed on a hotplate and allowed to 'fume to
near dryness'. (I seem to remember this could be a bit problematic as
one couldn't cover the beakers and there was always a danger of grot
dropping in if your fume cupboard was less then immaculately clean.
Also seem to remeber that it took a while). This is allowed to cool and
then another 3ml HClO4 was added and the process repeated. It's then
repeated a third time.
3. After the final cooling 1ml HClO4 and 10-15ml of deionised water are
added and the beaker heated to facilitate the final dissolution. These
solutions are then diluted to 100ml and stored for analysis.
4. Blanks are prepared by fuming 10ml HF with 9ml HClO4, adding 1ml
HClO4 and then diluting to volume.
This method is taken from the appendix to A. Sheridan (1989) Pottery
production in Neolithic Ireland: a petrological and chemical study. In
J. Henderson (ed.) Scientific Analysis in Archaeology. Oxford
University Committee for Archaeology: Oxford. Pp 112-135. It is, I
think, pretty typical.
I'm sure I could find some more detailed methodologies hidden away in
various theses here if that would be helpful.
One final thought though. Have you considered using laser ablation?
Could save you a lot of hassle if you can find standards.
On Tue, 17 Aug 1999 10:08:35 +0900 "M. E. Hall" <[log in to unmask]>
> Hi, I was wondering if someone out there would like to discuss
> various ways of dissolving pottery and geologic standards for ICP-MS.
> Off-line or on-line is fine.
> Most of the papers I've gotten a hold of just say HF-HNO3 solutions
> (or HClO4-HF), and don't go into detail. Either that or if someone could
> provide a good solid, detailed reference that would be handy (here in Japan
> my library access to browse is limited and it helps to have specific
> references when going to the Diet library....).
> I'm trying to measure the REEs
> and some of the transition metals. I'm using Geol. Survey of
> Japan standards JG2 and JB3 to monitor precision and accuracy. From the
> values I'm getting, its clear I've got a problem in either the disolution
> or somewhere else....
> Sorry to start Tuesday off with such a dumb question,
> Mark Hall
> [log in to unmask]
> (PS--I'm normally an XRF or microprobe user, but for some dumb reason,
> I decided ICP-MS for this current project.....)
Department of Archaeological Sciences
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