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From: larry@kitty.UUCP (Larry Lippman)
Newsgroups: sci.chem,sci.bio
Subject: Re: Need help with chemical analysis
Summary: Not a particularly "pure" substance...
Keywords: diatomaceus, diatomite
Message-ID: <3158@kitty.UUCP>
Date: 12 May 89 01:35:05 GMT
References: <113@merrimac.edsdrd.eds.com>
Distribution: usa
Organization: Recognition Research Corp., Clarence, NY
Lines: 64

In article <113@merrimac.edsdrd.eds.com>, ceg@edsdrd.eds.com (Carlos Galarce) writes:
> I need some help with a chemical compound I am told is diatomaceus earth. It
> is supposed to be mostly SiO2(~95%), with some other components. I guess this
> stuff is used in filtering processes. 

	Actually, the percent composition of silicon dioxide in diatomaceous
earth ranges between 85% and 90%.

> 	1) How do I go about getting it tested for its chemical components?

	At a chemical testing lab. :-)  Seriously, though, WHY do you want
to have this material tested?  The simple truth of the matter is that
diatomaceous earth is not a particularly pure filter material; it's fine
for swimming pool filters and the like - but not for applications where
purity of filter materialis of great importance.

> 	2) What test(s) should be run on the compound for analysis?

	If I were _serious_ about this effort, I would look for Total
Organic Carbon (TOC), carbonate ion, sulfate ion, and then run say,
ICP (Inductive-Coupled Plasma) emission spectroscopy to asertain
elemental composition.
 
> 	3) Where is a good lab that can do the test (hopefully in the 
> 	   midwest). Do universities do this kind of test?

	I won't recommend a particular commercial lab, but as a clue
you may wish to check membership directories of AOAC (Association of
Official Analytical Chemists) and ASTM (American Society for Testing
MAterials).  Some universities offer analytical services to private
industry.

> 	4) What amount of the compound is needed for the test(s)?

	10 grams would be a rather generous sample.

> 	5) About how much would I expect to pay for the test(s)?

	For the above tests and a formal report, most commercial testing
laboratories would charge between $ 200.00 and $ 500.00.
 
> 	6) In what form are the test results delivered to me?

	Generally in the form of a formal "test report", which may or may
not contain a copy of say, the ICP elemental scan report.

> 	Is there anything like a certified lab. (a seal of approval from
> somewhere).

	Not for general analytical testing (there is state certification
for environmental and clinical testing, though).  However, AOAC and ASTM
member organizations are usually a safe bet.

> 	7) How much does this stuff cost in large quantities?

	Check out a copy of OPD Buyer's Guide or Chemical Week Buyer's
Guide for vendors and give 'em a call.  I have some diatomaceous earth
in my lab, but laboratory prices for its use as a filter aid and as
a chromatograph column packing bear no relationship to quantity pricing.

<>  Larry Lippman @ Recognition Research Corp. - Uniquex Corp. - Viatran Corp.
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