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Methods for easy determination of Ni, Cu, Zn in metal samples

Q. I am looking for a simple method of determining the presence of, and, ideally, the concentration of a few base metals (Cu, Ni, Zn) and iron/steel in small metal samples. Accuracy is not paramount, and I would be thrilled if I could identify a simple method that could identify concentrations to ± 1% or even ± 5%. Destructive testing would be fine.

From the question, it is clear that I am not a professional finisher, nor a professional chemist. However, I do have a need to identify metal content of small (1" diameter, .2" thick) samples. The only easy method that I have been able to locate is XRF, but I am loathe to spend $30K+ on a unit. I have looked at many internet groups (scrap metal, coin collecting, casting, etc.), but this group seems to have the most sophisticated readership and discussion. So, I am throwing this out in the hopes that someone can point me in the right direction.

I have looked in a number of analytic chemistry textbooks (some new, some old), but the processes described there seem to be rather complicated. Perhaps the only route is to hire a chemist to teach me how to do it. My preference is always to attempt to work things out on my own, thus this post.

Other than XRF, eddy current sensors seem to hold out some hope, but even the device manufacturers indicate that, while possible, it is a bit of a stretch.

Do any of you have suggestions for a test or suggested references for further study?

Thanks very much!

Kenneth East
non-plating industry - Austin, Texas
February 3, 2008

Wow, thanks very much for the responses.

My intuition told me that the processes that I'd seen in the analytical chemistry books was too complicated, which was more or less confirmed here. Too complicated for a non-chemist anyway.

I can't say that I'm happy with the answer, but, the truth is the truth.

My (perhaps naive) hope is that the arc spectrometer might cost significantly less than the XRF. A lower cost might help to offset the loss in convenience due to the arc spectrometer being at least twice the size of the handheld xrf units.

Another consideration is that I will, from time to time, travel internationally with the unit. It may be unfounded, but I have a concern that the XRF unit might cause more problems, or at least delays, when going through customs. Tube based units might not be so bad, but I'd have to expect units with radioisotope sources to set off alarms.

It sounds as if either technology produces the results that I need. Please correct me if I am wrong. If I'm right, arc spectrometry is probably the way to go, even if it is equivalent in cost to XRF.

It is still hard to bring myself to part with $30K+ for this for a new unit. I've called around but have yet to find a small used arc spectrometry unit. If anyone has suggestions, I'm all ears.

Thanks again for the help.

Best Regards,
Kenneth

Kenneth East [returning]
- Austin, Texas

A. Try to find old Fritz Feigl's book on spot testing ⇦[this on AbeBooks or eBay or Amazon affil links] .
Andrew Holmes: "Rapid Spot Testing of Metals" ⇦[this on Amazon affil linksaffil links] is very good book too, but more expensive (cca 120 USD). Hope it helps and good luck!

Goran Budija
- Cerovski vrh Croatia

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ADDITIONAL RESPONSE,

Same analysis can be obtained via:
- Atomic Absorption Spectrophotometry (AAS) ⇦this on eBay or Amazon [affil links]
- Titrations (use GE book tests)

Jose Castellanos
- Minneapolis, Minnesota