....more on calcite, anti-freeze, etc.

Scott Carpenter pointed out that...
>The problem of anti-freeze is one of how easily it is removed from the
>sample - thus solubility of anti-freeze and the porosity of the sample
>must be considered.  

>Also,  can't you drain the anti-freeze, clean the saw (thoroughly) and
>fill it with water ?

Yes, Scott, you are absolutely correct on both of the above points. Also, i
think a comparison between samples cut using water & new anti-freeze
(followed by cleaning to remove the anti-freeze) might be instructive at the
outset... just to see if there are really any differences. 

>Particulate matter from previous cuttings should not be a problem unless
>the pores (if there are any) fill with debris...repeated ultra-sonic
>cleaning will help here.  

The propensity for a process, such as sawing, to cause contamination in a
sample is going to increase as sample size (or C & O content) decreases. I
don't know what sort of samples Ethan is working with, but with small
samples, i don't think even the most scrupulous cleaning measures would be
good enough if that sample was cross-contaminated with C- & O- rich
particulates (especially other carbonates!). Maybe i sound TOO cautious, but
i've had to do too many analyses over again because of stuff just like this!

Dave Wayne
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Chemical Sciences & Technology Div.
CST-8, MSG-740
Los Alamos National Laboratory
Los Alamos, NM USA 87545
Phone: 505-665-5933 <OR> 505-667-9868
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