Author Topic: Carbonate staining  (Read 958 times)

Nick Bulloss

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Carbonate staining
« on: March 15, 2017, 07:42:59 am »
Hi All,
I have a vague recollection of reading somewhere that analyzing stained carbonates could be a problem for an EPMA, something about coating detectors etc. I have a student that would like to analyze carbonates that are stained with potassium ferricyanide - are there any potential issues for my instrument?
Thanks for helping my pitiful memory!
Nick

Probeman

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Re: Carbonate staining
« Reply #1 on: March 15, 2017, 08:53:53 am »
I have a vague recollection of reading somewhere that analyzing stained carbonates could be a problem for an EPMA, something about coating detectors etc. I have a student that would like to analyze carbonates that are stained with potassium ferricyanide - are there any potential issues for my instrument?
Thanks for helping my pitiful memory!

Hi Nick,
I could be missing something but in Cameca instruments, nothing volatized in the sample chamber can reach the spectrometer detectors or crystals, due to the column separation windows, but maybe you are speaking of the BSE detectors?

I know that our engineer has had to clean off volatized epoxy from the samples that has been deposited on our BSE detectors.  The larger issue for us has been trying to "balance" the BSE detector segments electronically so the field appears equally luminated.  See here:

http://probesoftware.com/smf/index.php?topic=583.msg3318#msg3318

john
« Last Edit: March 15, 2017, 08:58:27 am by Probeman »
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Nick Bulloss

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Re: Carbonate staining
« Reply #2 on: March 15, 2017, 09:46:17 am »
Hi John,
I was thinking of the BSE detector in particular, given its proximity to the sample, but also potentially contamination of the light optics components in the lower part of the column. I plan to use relatively low beam currents - I'm only really interested in the major elements in the carbonates. I don't think this would be an issue but again I have this hazy memory giving me pause!
Nick

ericwgh

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Re: Carbonate staining
« Reply #3 on: December 13, 2017, 05:22:23 pm »
Can I follow up on this? Same question and little carbonate experience.

Does this staining method affect the Fe content of the carbonate? Or are any other minor elements (Sr, Mg) leached out?

I also have no idea whether thin sections need to be repolished after the staining to produce a flat non-pitted surface for EMP analysis. The student that is interested in this wants to have polished stained thin sections made commercially, and my interpretation from reading the Cambridge website below is that you need a glass cover slide to archive the staining, since "stain is delicate and is easily removed".

https://www.esc.cam.ac.uk/resources/facilities/laboratories/carbonate-staining

Any advice?

Many thanks
Eric Hellebrand
Univ. Hawaii