Dear Linda;

just a thought on the problem with the quartz liners. The height of the
packing in the oxidation tube is quite important and if incorrect it can
lead to poor combustion. With the nickel liners, you usualy put in an extra
10mm of chromium oxide plus 5mm wool under the nickel liner plus 5mm wool on
top of the chromium oxide in the nickel liner. In total an extra 20mm that
is not there if you use the quartz liners.

If you use the quartz liners, It is important to place an extra 10mm
chromium oxide in the combustion tube with 5mm quartz wool on top of this. I
then place 5mm of quartz wool to plug the quartz liner so that the total
height is the same as if you were using the nickel liners.

It is also important to make sure that the holes in the side of the liners
are not blocked with ash after you clean them up. Otherwise you may get
problems with oxygen reaching the sample.

Hope this helps

Jon Fear....

Senior Laboratory Technician
Department of Agricultural Sciences
Imperial College at Wye
Wye
Ashford
Kent TN25 5AH.

Tel:020 759 42879
Fax: 020 759 42640
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