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Date: | Wed, 23 Apr 2008 12:28:23 +0100 |
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Hi Dan
A better forum for your question would be the plasmachem list, which deals with all things related to plasmaspectrochemistry and more. The link to join is http://listserv.syr.edu/scripts/wa.exe?SUBED1=plasmachem-l&A=1 or google for plasmachem list.
A basic answer to your questions.
1) depends on the nature of the organic material, the ablation conditions and instrumental setup. The cones are the most likely area to clog up and maybe the extraction lens. The only way to find out is to try. Cones are easy to clean, ultrasonication in water usually does the trick, see the plasmachem archives for other methods using 'stronger' solvents. Lens cleaning requires more knowledge either from an in house expert or the manufacturers engineers, once learnt from them you may be able to clean lenses yourself.
2) C on a quad ICP-MS is not really feasible due to air entrained in the plasma. Having said that you may be able to monitor 13 C depending on the instrument although expect high background levels. S is similar, due to O2 polyatomic interferences, although 33S or 34 S may again be possible.
When normalising to another element in the sample you have to have 100% homogeneity for this element or biased results occur. Another approach is to tee in a desolvated internal standard into the transfer line post ablation.
Yours
Rob
________________________________________
From: Stable Isotope Geochemistry [[log in to unmask]] On Behalf Of Dan Sinclair [[log in to unmask]]
Sent: 23 April 2008 11:01
To: [log in to unmask]
Subject: [ISOGEOCHEM] Laser-ablation mass spectrometry of organic matrices
Hi All,
Does anyone have experience with laser-ablation mass
spectrometery (specifically ICP-MS) on organic
samples? I'm considering attempting some analyses on
antipatharian coral skeletons, which are made from
gorgonin - a tough chitinous organic material.
I have two questions:
1) Does laser-ablating organic material create
problems for the instrument (such as contamination of
the instrument, major shifts in sensitivity, and/or
'gumming up' of the plates and cones and detectors and
such)? If so, is there an effective way of 'cleaning'
the instrument after such analyses.
2) I'm used to CaCO3 analyses where one normalises all
analyses to calcium (to correct for fluctuations in
ablation efficiency). What would one do for an organic
material? I don't know if there is an effective way of
monitoring C on quadrapole ICP-MS. Maybe there is
another component of the material that could be
monitored to normalise ablation (S perhaps?)
I'd be grateful for any help or advice!
Cheers,
Dan Sinclair
Scottish Association for Marine Sciences
Dunstaffnage Marine Laboratories
Oban, Argyll PA37 1QA
Scotland
Ph: +44 (0)1631 559 412
Fax: +44 (0)1631 559 001
http://www.sams.ac.uk/research/sams-scientific-staff
http://www.ig.utexas.edu/people/staff/dan/
Get the name you always wanted with the new y7mail email address. www.yahoo7.com.au/y7mail
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