We use this system for the in-situ analysis of trace and rare earth elements in minerals such as garnets, cpx, and other silicate and carbonate samples.
Major element composition is used as internal standard for concentration determinations, so most samples are analysed first by the electron probe.
Whenever possible, sections of samples should be prepared 100 micron thick compared to normal thin sections which may only be 30 micron. The size of the glass slide should be 46-48mm long x 25-30 mm width and also conveniently fits the sample holder for the electron probe. Separated grains may be mounted and polished in an epoxy resin block 26 mm in diameter.
Any graphite coating (for probe analysis) should be removed prior to ICP-MS analysis by gentle polishing with a fine diamond paste, rinsed clean and dried.
Finding specific spots to analyse on the LA-ICP-MS can be tricky and time-consuming: users are strongly encouraged to bring along printouts of sample 'maps'. Small marks can also be made on the edges of the slide to help locate some of the smaller features. The microsope on the laser is not as good as some of the dedicated microscopes you might be accustomed to.
The maps should be printed as your eye sees the sample, which is unfortunately the reverse of the maps needed for the probe.
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