# Testing Silver Purity using ICP



## Eamonn (Apr 9, 2013)

Hi 

I have bought a 25 ozs bar of 999 silver.
I want to check the if it is actually 99.9 % pure.
My Idea is to take some small samples from the bar, weigh to 0.1miligamme and disolve in nitric acid.
Dilute to a calculated 10ppm then check on an ICP to see if It is actually 10ppm.

Does anyone know if this method would work.

For those who don't know an ICP (Inductively Coupled Plasma) is modern technology for testing low levels of metals in liquid.
The liquid is sucked into a Plasma (Very Hot 10000 deg C) and the light given off is related to the amount of metal in the liquid.

Cheers


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## Dan Dement (Apr 9, 2013)

Eamonn,

The first test I would run is a SG test. If you want to be sure of the purity of the entire bar and make sure it is not filled with another metal, an SG test will give you a very good INDICATION to proceed to other tests. No, it's not 100% accurate but it is non destructive and all it's going to do is get it wet. To me, to know that it has the proper SG is far more important an ICP. If it's right on, great go ahead on the ICP but if it's wrong, you might have 100% silver on the outside and 100% lead on the inside. ICP is not going to catch that. An ICP will get you right on but a good XRF will give you good results also but only on the outside. Ever seen all the fake filled bars running around? 

Good Luck,
Dan


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## Westerngs (Apr 9, 2013)

Eamonn,

Your ICP method needs some work.

First off, do not try to quantify the silver via ICP. Instead, quantify the trace impurities and subtract those from 100% to find % Ag. That is the accepted ASTM practice.

I would dissolve 0.5 grams silver sample, dilute to 50 ml and analyze that for trace impurities. Obviously, you will need suitable standards and matrix match the acid content of the standards and samples.


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## Anonymous (Apr 9, 2013)

Let me get this straight.......

You bought 25 oz silver ($699.25... spot price right now) worth of silver and had no way of checking on the purity of the silver, yet, you use terminology like ICP (Inductively Coupled Plasma) and you can't even tell if you bought a piece of lead or silver?... or a combination of both?

If it were me, I'd simply core out a couple holes *completely through the bar* and put it in nitric acid. If I can afford testing equipment, or pay to test what I really have, then I'm sure I can come up with a simple acid test to test my material.



Kevin


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## Eamonn (Apr 12, 2013)

All
Thanks for the info. 
Very usefull.


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