I believe the tarnish on silver capsules in not an oxide but silver sulfide. 

Once upon a time I had some samples in the lab that had been sitting for a number of years and the silver was very tarnished. As a test, we removed the references and ran them along with some fresh ones in newly baked silver capsules. They were indistinguishable.  

With that said, I still like to bake silver capsules to ensure they are clean.


Yale Analytical and Stable Isotope Center
Yale Institute for Biospheric Studies
21 Sachem Street
New Haven, CT 06511
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On Dec 4, 2018, at 1:39 PM, Scott Hughes <[log in to unmask]> wrote:

The oxidation on silver capsules can be removed by heating in air at 375oC for one hour prior to use.
Scott Hughes
EA Consumables, Inc.
5090 Central Hwy STE 3A
Pennsauken, NJ 08109-4637
Toll Free: 855-695-1312 x301
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----------------------- Original Message -----------------------
From: "Munizzi, Jordon" <[log in to unmask]>
To: [log in to unmask]
Date: Tue, 4 Dec 2018 18:33:21 +0000
Subject: [ISOGEOCHEM] Oxidized silver capsules
Hi everyone,

In the wild days before it became a cost center, someone purchased many thousands of silver capsules for our TC/EA. Unfortunately, most have oxidized just in time for us to get our TC/EA up and running. Even some of the capsules that appear unoxidized are giving us blank issues.

Has anyone tried to salvage oxidized silver capsules? I'm thinking of setting up something to stream hydrogen over a load of capsules while gently heating them, but perhaps there's another way? Preferably one that doesn't involve the phrase "just throw them out and buy more"?

All input is much appreciated,
Jordon Munizzi, PhD
Research Facility Manager
Department of Earth and Environmental Sciences
University of Kentucky

Ph: (859) 270-9177
Fax: (859) 323-1938