Au+++   !!!   I was using an ICP standard which was probably in the form 
of Au+.  Thanks for clearing that up for me, Otto.

Duane Miller
Analytical Lab Manager
APL Engineered Materials, Inc.
Urbana, IL

"PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's)." 
<[log in to unmask]> wrote on 01/26/2010 04:40:59 PM:

> The gold was supposed to be added as Au+++, which is also an oxidizer
> and hence contributes to keeping Hg in solution. 
> 
> 
> Dr. Otto Herrmann, Ph.D., C.Chem.
> Manager, Analytical and Environmental Services,
> Kinectrics Inc.
> 2-800 Kipling Ave., (Unit 2), Bld. KJ135
> Toronto, ON
> Canada
> M8Z 6C4
> Phone: 416-207-6262
> Fax:     416-207-5550
> e-mail: [log in to unmask]
> 
> -----Original Message-----
> From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's).
> [mailto:[log in to unmask]] On Behalf Of Pappas, Richard
> Steve (CDC/CCEHIP/NCEH)
> Sent: Tuesday, January 26, 2010 5:24 PM
> To: [log in to unmask]
> Subject: Re: gold and silver
> 
> It sounds like a Christmas song that Burl Ives (who?) used to sing,
> "Silver and gold, silver and gold..."
> 
> The principal behind adding gold is that it is also a soft acid cation
> like mercury. Anything mercury might stick or coordinate with, gold
> would too. By having the gold in excess, one blocks "sticky sites." In
> addition, both Hg and Au are easily reduced, so by having gold in
> excess, the Au is more likely to be reduced by any reducing substance
> than the Hg. Silver is also a soft acid cation and easily reduced, so
> the principal would be the same with certain caveats(!!).
> Silver is easily reduced even by exposure to light. I don't know the
> procedures that you found, but be aware that as a long term solution
> stabilizer, gold would probably be your better choice. Light exposure
> catalyzes reduction and precipitation of silver. As the metallic silver
> comes out of solution, Hg may amalgamate with it or otherwise stick to
> the precipitate. 
> I agree with Duane. Chloride in high concentrations, especially > 1.2 M
> (though lower concentrations still help). This takes Hg2+ toward the
> [HgCl4]2- complex. By shifting the equilibrium away from free Hg2+ ion,
> one shifts the equilibrium away from metallic mercury. Ag, however is
> not soluble at some Cl- concentrations. There ARE higher chloro
> complexes with Cl- that are soluble, but hitting that without losing any
> and keeping it there through dilutions may not be easy. I would stick
> with Au, or choose a soluble chelator with a sulfur ligand like
> pyrrolidinecarbodithionic acid ammonium salt (APDC) if you want
> something other than HCl. APDC requires much less.
> 
> R. Steven Pappas, Ph.D. 
> Emergency Response & Air Toxicants Branch 
> Centers for Disease Control & Prevention 
> 4770 Buford Hwy. NE, M.S. F-44
> Atlanta, GA 30341-3717 
> Phone 770-488-4661 
> [log in to unmask] 
> 
> 
> -----Original Message-----
> From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's).
> [mailto:[log in to unmask]] On Behalf Of Michael Murphy
> Sent: Tuesday, January 26, 2010 4:57 PM
> To: [log in to unmask]
> Subject: gold and silver
> 
> Dear All,
> 
> I have a question regarding stabilizing Hg solutions with silver.  I
> have 
> had good luck with stabilizing Hg solutions with Au (both as chloride
> and 
> nitrate salts) and in fairly concentrated hydrochloric acid solutions.
> 
> However, I have come across a method indicating the use of silver
> instead 
> of gold.  I am not familiar with this and have not been able to find a 
> ready reference.  Does anyone have experience with this arrangement?
> 
> Always willing to learn something new ....
> 
> Thanks,
> 
> Michael Murphy
> Research Scientist
> Intertek USA
> Whitehouse, NJ
> 
> 
> 
--------------------------------------------------------------------------------
> This transmission contains information which may be confidential and
> which may also be privileged.  It is intended for the named 
> addressee only.  Unless you are the named addressee, or authorized 
> to receive it on behalf of the addressee, you may not copy, use, or 
> disclose it to anyone else.  If you have received this transmission 
> in error, please contact the sender.  Thank you for your cooperation. 
> 
--------------------------------------------------------------------------------
> Kinectrics Inc.  800 Kipling Avenue, Unit 2  Toronto, Ontario, Canada 
M8Z 6C4