**At_Symbol_Here**Jerry's post,

EPA 3050 may refer to a slightly different procedure. The original post did  
not make mention of H202 reagent.

Depending on the absence or presence of H202, 3050 or 200.2 may be more  
relevant.

Regards,
Craig


On Nov 2, 2010 7:22pm, conway.csa**At_Symbol_Here**gmail.com wrote:
> Margaret,

> Here is the information I gathered. Note though, that I do not have  
> personal experience with soil digestions.

> The engineer I spoke with said that at a universities, the duct work is  
> most likely carbon steel, galvanized steel or stainless. A quick test is  
> to get a decent magnet and test if it sticks. If it sticks, its not  
> stainless and you should not do the procedure. If it doesn't stick then  
> you've narrowed it down to stainless steel, aluminum or fiberglass. If  
> you don't have the experience to tell the difference between aluminum and  
> stainless steel then wait for verification from building maintenance  
> coridinator. Also note: the engineer warned a common building mistake is  
> for them to install stainless steel ductwork, but use a cheapo exhaust  
> fan with aluminum blades, you may want to verify that too.

> Additional link: The CSB Guidelines for fume hoods (pg 10 indicates it  
> should be stainless steel, but might be galvanized)
> http://www.ehs.ucsb.edu/units/labsfty/labrsc/chemistry/fhguide_07.pdf

> The link below is the EPA approved procedure for hot plate assisted aqua  
> regia sample digestion. Note specifically procedure section 11.1.2, as it  
> pertains to covering beaker and the suggested temp of 85C while  
> uncovered, 95C when covered.

> -Procedure 11.1.5 is an under emphasized step in my opinion. As the msds  
> points that its to avoid an explosion hazard.

> Lastly, I myself am curious & worried about a strong reaction. Note the  
> MSDS below reactivity profile with metals and hydrocarbons. I recommend  
> following the EPAs guidelines of smaller reactant volumes (25ml is more  
> than I would want to try this experiment with)

> http://water.epa.gov/scitech/swguidance/methods/bioindicators/upload/2007_07_10_methods_method_200_2.pdf

> This link (below) is the msds for aqua regia (HCL + HNO3) CAS

> http://www.docstoc.com/docs/26426711/SAFETY-DATA-SHEET-AQUA-REGIA

> Regards,
> Craig
> BS Molecular Biology


> On Nov 2, 2010 5:05pm, Margaret Rakas mrakas**At_Symbol_Here**smith.edu> 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,
> >
> > Margaret
> >
> >
> >
> >
> >
> >




**At_Symbol_Here**Jerry's post,

EPA 3050 may refer to a slightly different pr
ocedure. The original post did not make mention of H202 reagent. 

Depending on the absence or presence of H202, 3050 or 200.2 may be more r
elevant. 

Regards,
Craig



On Nov 2, 2
010 7:22pm, conway.csa**At_Symbol_Here**gmail.com wrote:
> Margaret,
> 
> Here is the information I gathered. Note though, that I do not have p
ersonal experience with soil digestions.
> 
> The engineer 
I spoke with said that at a universities, the duct work is most likely carb
on steel, galvanized steel or stainless. A quick test is to get a decent ma
gnet and test if it sticks. If it sticks, its not stainless and you should 
not do the procedure. If it doesn't stick then you've narrowed it d
own to stainless steel, aluminum or fiberglass. If you don't have the e
xperience to tell the difference between aluminum and stainless steel then 
wait for verification from building maintenance coridinator. Also note: the
 engineer warned a common building mistake is for them to install stainless
 steel ductwork, but use a cheapo exhaust fan with aluminum blades, you may
 want to verify that too. 
> 
> Additional link: The CSB Gu
idelines for fume hoods (pg 10 indicates it should be stainless steel, but 
might be galvanized) 
> http://www.ehs.ucsb.edu/units/labsfty/labrs
c/chemistry/fhguide_07.pdf
> 
> The link below is the EPA a
pproved procedure for hot plate assisted aqua regia sample digestion. Note 
specifically procedure section 11.1.2, as it pertains to covering beaker an
d the suggested temp of 85C while uncovered, 95C when covered. 
> <
br />> -Procedure 11.1.5 is an under emphasized step in my opinion. As t
he msds points that its to avoid an explosion hazard. 
> 
>
 Lastly, I myself am curious & worried about a strong reaction. Note the MS
DS below reactivity profile with metals and hydrocarbons. I recommend follo
wing the EPAs guidelines of smaller reactant volumes (25ml is more than I w
ould want to try this experiment with)
> 
> http://water.ep
a.gov/scitech/swguidance/methods/bioindicators/upload/2007_07_10_methods_me
thod_200_2.pdf
> 
> This link (below) is the msds for aqua 
regia (HCL + HNO3) CAS 
> 
> http://www.docstoc.com/docs/26
426711/SAFETY-DATA-SHEET-AQUA-REGIA
> 
> 
> Regards
,
> Craig
> B.S. Molecular Biology
> 
> 
> 
> On Nov 2, 2010 5:05pm, Margaret Rakas mrakas**At_Symbol_Here**smith.edu&g
t; wrote:
> >   
>   
> >       Good afternoo
n,    
> >     
> 
> >       I have a researc
her who wants to perform acid digestions involving about 20 mLs of concentr
ated hydrochloric acid and 5 mLs of concentrated nitric acid which are mixe
d with her soil, then slowly heated to 95C until most of the acid has evapo
rated. =A0=A0The methodology, developed by outside researchers, is outlined
 in a journal article which makes no mention of the use of scrubbers, speci
al fume hood lining, etc.    
> >     
>     
> 
>       The researcher will be wearing a face shield, rubber apron, gogg
les, lab coat and thick nitrile gloves, with tape around the glove/labcoat 
interface. =A0I think we have the PPE down pat. =A0    
>    

> >     
> >       The process is planned to be carried ou
t in a fume hood, using an open vessel on a hot plate. =A0My concerns is wh
ether we should be using some sort of capture system or scrubber for the ac
id that is evaporated. =A0I 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. =A0The researcher is planning on doing somewh
ere 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 ins
talled..' [Matusiewicz] but no reference to actually how this is done. 
=A0    
>     
> >       Any suggestions, citations, etc
. would be most helpful..    
> >     
> >       than
ks to all,    
> >     
> >       Margaret    
&
gt; >     
> >       
> > 
> >     
> >   
> >
--000e0cd14b5654782504941a6907--

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