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Date: Wed, 3 Nov 2010 07:54:37 -0400
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Date: Wed, 3 Nov 2010 08:55:38 -0400
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: Kristi Ohr <kohr**At_Symbol_Here**AMHERST.EDU>
Subject: Re: Acid Digestions

You could have them set it up like a simple distillation under nitrogen 
flow, and then have the outlet bubble through a sodium hydroxide 
solution.  If you don't know what I mean, I can send you a picture.
 
Kristi

________________________________

From: DCHAS-L Discussion List on behalf of Margaret Rakas
Sent: Tue 11/2/2010 5:05 PM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: [DCHAS-L] Acid Digestions




Good afternoon, 



I have a researcher who wants to perform acid digestions involving about 
20 mLs of concentrated hydrochloric acid and 5 mLs of concentrated 
nitric acid which are mixed with her soil, then slowly heated to 95C 
until most of the acid has evaporated.   The methodology, developed by 
outside researchers, is outlined in a journal article which makes no 
mention of the use of scrubbers, special fume hood lining, etc. 



The researcher will be wearing a face shield, rubber apron, goggles, lab 
coat and thick nitrile gloves, with tape around the glove/labcoat 
interface.  I think we have the PPE down pat.   



The process is planned to be carried out in a fume hood, using an open 
vessel on a hot plate.  My concerns is whether we should be using some 
sort of capture system or scrubber for the acid that is evaporated.  I 
am trying to find out what the ductwork for the fumehood is made of, but 
it is not a stainless steel hood and I am betting the ductwork is not, 
either.  The researcher is planning on doing somewhere between 20-100 
samples, depending on how things go, so roughly 400 mLs to 2000 mLs of 
concentrated acid may be sent through the ductwork... 



I found one review article on acid digestions that stated "...acid 
digestion must be conducted in a fume cupboard with efficient scrubbers 
installed..' [Matusiewicz] but no reference to actually how this is 
done.   



Any suggestions, citations, etc. would be most helpful.. 

thanks to all, 

Margaret

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