Darryl Short's idea would not work for every soft acid cation metal, but ammonia DOES form soluble complexes with silver ion that should keep it more stable as the ion rather than being reduced, so that would be an option also. However, if you are using acidic diluent, I would stick with L-cysteine.
R. Steven Pappas, Ph.D.
Team Lead, Tobacco Inorganics Group
Centers for Disease Control & Prevention
4770 Buford Highway, NE
M.S. F44, Building 110
Atlanta, GA 30341-3717, USA
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). <[log in to unmask]> On Behalf Of Michael Szoltysik
Sent: Thursday, May 17, 2018 2:11 AM
To: [log in to unmask]
Subject: Re: Silver issue, Agilent 7700/7900
Thank you all for all the great input!!
I will try the L-cysteine option. Regarding solutions, those are prepared daily from a larger stock, that is finished after about 2 months (all stored in a cabinet away from light). I ruled out the solutions though, as the same are used on other 5 instruments of the same kind, and those work fine. On those problematic systems, all parts that touches solutions have been changed and replaced by completly new ones.
Eurofins Environment Testing Sweden AB
Development Chemist & Team Leader
Phone: +46 10 490 8133