Hello Peter,

I am agreed with Steven. I answered earlier to the list but the
message bounced back to me. So here again...

The only time it is happening to me is when I analyse for sulphur, so
the furnace is at 1000 degrees C because only one reactor is used,
but it happens after 3 or four days. Otherwise this is the same type
of shinny copper and purple. I was a bit worried the first time, so I
analysed it, the shinny bit is in fact the tin from the capsules,
obviously vaporized by the combustion.

Did you check the temperature of your furnace? Is there any chance
that the temperature reading is incorrect, and the thermocouple gives
a wrong reading?  just a thought... may be you are above 1000C.

Sorry for the double message Peter, but I wanted also to see if more
people experiment this for sulphur analyses, because despite being
normal when you analyse for sulphur, it can be quite a serious
problem.

Cheers,

Nathalie
--
<><><><><><><><><><><><><><><><><><><><><><><><><>
Nathalie V. Grassineau
External Service Manager
Stable Isotope Laboratories
Department of Geology
Queen's Building
Royal Holloway University of London
Egham
Surrey TW20 0EX
UK

e-mail address : [log in to unmask]
Tel +44 (0)1784 44 3810 (office)
Tel +44 (0)1784 44 3629 (lab)
Fax +44 (0)1784 47 1780
Webpage:  http://www.gl.rhul.ac.uk/staff/ng.html
        http://www.gl.rhbnc.ac.uk/silab
<><><><><><><><><><><><><><><><><><><><><><><><><>