Summary for uv-vis plating bath analysis Discussion
UV-Vis spectrophotometry is discussed as a possible tool for plating bath analysis, but the thread makes clear it is not a general-purpose method for directly measuring metal content like nickel concentration. In the main question, Ricardo Higgins says he has been asked to add PLC-based automated bath data logging for a nickel bath and is now being pushed to use UV-Vis, which he notes is uncommon. In an earlier related question, Robert Winkky asked what plating solutions can be accurately measured with UV/Vis and where to find methods for electroless nickel. The answerer says that, with appropriate standards, UV-Vis could be used for a quick go/no-go test of Ni content, and that trace-level methods may work for whatever inhibitor is added to an electroless nickel solution. The overall takeaway is cautious: UV-Vis may help with specific colorimetric or trace analyses, but it is not presented as a reliable universal nickel assay.
Quickstart:
Spectrophotometry basically involves analyzing the different light wavelengths a material emits or allows transmission through to determine the constituents of something.
UV-Vis uses UltraViolet and/or Visible light transmission, as opposed to Infrared light transmission, and as opposed to Atomic Emission Spectrophotometry where constituents are ignited to analyze what wavelengths they emit.
But responders don’t seem to feel that UV-Vis is an appropriate tools for analyzing metal content like nickel concentration.
Read on, join in …
(this entry appended to this thread by editor in lieu of spawning a duplicative thread)
Q. I am a recovering EE now working in a plating shop. I have been tasked with adding a PLC based automated bath data logging system. I was fine with voltage, current and temperature.
The direction has changed now. I am being asked to do metal content in a Ni bath, using UV-Vis. This is not a common thing! Does anyone have any guidance? ⇦ Answer?
Ricardo Higgins
employee – Poway, CA, USA
April 29, 2026
⇩ Similar, related, Q&As — oldest first ⇩
“Colorimetric Analysis of Metal Finishing & Metal Working Solutions & Effluents”
by Aubrey Knowles
on Amazon
<!–UTL 9/6/25
AbeBooks
or
–>
<!–UTL 9/6/25
eBay
or
–>
(affil link)
Q. We have received a Perkin-Elmer Lambda UV/Vis spectrophotometer to use for analysis on mainly our electroless nickel baths … and whatever else we can do with it is just bonus. I have tried to buy a copy of
“Colorimetric Analysis of Metal Finishing & Metal Working Solutions & Effluents”, by A. Knowles ⇨
for some methods, but I cannot find it anywhere. My questions are
1. What is a place besides the aforementioned book to find methods for analyzing our EN plating solutions?
2. What types of plating solutions can be accurately measured using UV/Vis spectrophotometry?
(We do zinc, cadmium, copper, electroless and electrolytic nickel, chromates, chrome, anodizing, silver, gold, tin, tin-lead, zinc phosphate, manganese phosphate, and zinc-nickel.)
Robert Winkky
Plating shop engineer – Elmira, New York
August 12, 2008
Ed. update May 2026: Knowles is currently available on Amazon ⇨
A. Nice piece of equipment!
Given appropriate standards, you could do a quick “go-no go” test on the solution’s Ni content. There are also methods for trace level metals that you might apply to whatever inhibitor is added to your EN solution.
Dave Wichern
Consultant – The Bronx, New York
A. Lots of luck! I want a copy and planned to order a copy from AMS International, but out of print and not in stock. No luck with Amazon or www.abebooks.com for used copy. Maybe you can do what I plan…order a copy on interlibrary loan and copy what I need.
Doug Hahn
– Indianapolis, Indiana
Ed. update: Although that book is now available from Amazon, worldcat.org shows that many university libraries have copies.
A. I have a copy of Knowles book and have found it to be very helpful. It was also published in Europe by Finishing Publications. The book is still listed at this link:
finpubs-dwh.demonweb.co.uk/books-and-cd-roms/new-books/ ⇩
Hopefully they are still publishing. If not, if they will provide copyright exception, I would be happy to copy specific methods for you.
Sincerely,
Ira Donovan, M.S.F.
Kansas City, Missouri
Ed. update May, 2026: Sadly, Dr. Anselm Kuhn passed away on Jan. 13, 2026. R.I.P. to a fine electrochemist.
We’ve been unable to find Finishing Publications Limited for the past couple of years and suspect Dr. Kuhn’s health or energy level at 89 didn’t permit keeping it running. However, the Knowles book is currently available on Amazon at the link shown above.
UV/Vis instruments for plating bath analysis?
I am a chemist for a small research company, and I finally got the go ahead to purchase a UV/Vis instrument. Could someone recommend a good model?
We have an Iron/Nickel bath and are thinking of bringing in a ternary bath as well, will a UV/Vis be able to handle the more complex solutions, or will the peaks tend to overlap and obscure each other?
Also how critical is the range, I have found some inexpensive instruments but their range is 200 to 1000 nm’s, and if I wanted 190 to 1100 nm’s it would cost more, is the slight increase in range worth it? Finally does a dual beam help, I seem to recall it was mainly a means of eliminating background and stabilizing the baseline? Thanks for any help or suggestions it is greatly appreciated.
Richard Caldwell
chemist in a small plating research company. – Seattle, Washington
April 6, 2009
Ed. note: Readers, please feel free to recommend wavelength range, dual beam or not, and any other types and specifications rather than brand names ( huh? why?). In addition to the other problems with brand names; their mention has several times led to a loss of aloha and a race to the bottom when a salesperson saw their competitor’s instrument suggested. 🙂
Thanks.
A. My first question is why do you want to use UV/Vis spectroscopy? As with all analytical techniques, it has its place, but for analysis of cations it is not ideal. If you want to measure iron and nickel, try either atomic adsorption spectroscopy (AAS)
⇦ on
or
Amazon [affil link] or ICP
⇦ on
[affil link]
. The former is cheaper than the latter, but ICP is faster and can do multiple elements in one go. These techniques are much more sensitive to Fe and Ni than UV spectroscopy and are easier to interpret.
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
A. I have worked in many plating labs and visited many more so I can confidently say that UV/Vis is a rarity and of very limited use. Saccharin and coumarin are possible uses but the former has a relatively simple titration and neither are routinely analysed. Most proprietary additives are not declared composition so no help there.
Most labs go for AAS as the first instrument, labs with plenty of funding (very few) may have an ion chromatagraph or an auto-titrator. Even research labs do very well with titration and a pH meter.
My preferred instrument is a polarograph. If a species is electroactive it can be determined. If it is not electroactive it is unlikely to affect a plating solution.
The answer to your original question is: Decide what analysis you are going to do and the instrument will select itself.
Geoff Smith
Hampshire, England
We have an AAS but it is time consuming, and I would love an ICP but the cost is prohibitive. UV-Vis instruments are pretty cheap right now and I was under the impression they would simplify my analysis.
I have seen articles in Metal Finishing
⇦ huh?
where they used it for Saccharin, and I thought you could use UV-Vis for metal analysis as well? I had envisioned using this to analyze for nickel, iron and saccharin simultaneously.
I used it in college for confirmation but never for determining specific concentrations. Can you run calibration curves of pure standards of the metals and saccharin and then use the peak height and location to pick out the concentrations of the individual anolytes in a solution with multiple anolytes? We have multiple metal cations in most of our baths and I am worried about the overlap of the peaks on UV-Vis.
The setup and calibration would be time consuming, but if it worked it would dramatically speed up my analysis while reducing the cost. We currently do have the AAS and use titrations for nickel so I would shift these to more of a QC control of the UV-Vis process in the hopes of saving time and chemicals. ⇦ Answer?
Richard Caldwell [returning]
– Seattle, Washington, USA