Date: Tue, 2 Nov 2010 16:17:56 -0500
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: Jerry King <jjk7**At_Symbol_Here**MIDWESTLABS.COM>
Subject: Re: Acid Digestions
In-Reply-To: <4CD044BD020000BA00021F23**At_Symbol_Here**gwsmtp1>

If you get EPA 3050 method (you can download it from the EPA website - SW846 on line ( - it will give the method as well as safety aspects.  It is a very commonly used method for environmental labs like ours.


On 11/2/2010 4:05 PM, Margaret Rakas wrote:

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,


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