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Help! RPP additive analysis


Q. Hello My name is Adrian and I am an exchange student at TU Delft were I am doing my final year research project. I have a big problem for 2 months NO results. I am doing the rate of additive breakdown in the electrolysis bath. I am using the Radiometer PST050 with a RDE rotating disk electrode and I am trying to make the analysis stable because the results are not repeatable. Now I want to to use the Autolab to do the measurements because I don't have the test cell to test the machine from Radiometer and I don't have any idea what to do to improve the analysis.

I use a brightener and a starter from Schlotter(?) in the electrolyte and for the analysis I am using the standard addition method for the brightener. With 2 or 3 addition and 95 ml of blank solution (just copper ions and CL- ions) then add 5ml of sample (the maximum conc. in sample is 0.25) and then add 2 or 3 additions of 100 µL 1% brightener. The software is varying the potential and records the current density. The machine is using a 3 electrode system (reference electrode- AgCl/sat. KCl; rotating disk electrode platinum; wire platinum electrode). If any of you know this type of measurement, worked with the Radiometer machine or with the Autolab to do this kind of analysis or know another way to measure the conc. of additives in the electrolyte solution please send it to me!

Best regards,

Carcel Radu Adrian
- Brasov, Romania


thumbs up sign Adrian, the best approach is to ask Schloetter how to analyze this as it is their proprietary product and they know exactly what it is. You also want to be careful to not accidentally compromise trade secrets, and talking to Schlotter about this analysis would help insure that you are not revealing details that are held as proprietary. Best of luck.

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey


A. There is a lot that I do not know, but I can not see how a rotating disc electrode is going to be able to analyze for brightener and breakdown. I sort of thought that ion chromatography was used for that. HPLC has been used for some plating analyses, but not many.The average shop can not afford either one of these instruments. Brightener is normally controlled by Hull Cell testing. This is an inexact science at best and is not easy to sort out when you have a 3 additive package. Some shops get to be really good at it mostly because they can directly compare Hull Cell results to tank results over a long period of time. The vendor's tech services will normally provide a check of the brightener package on a frequency directly related to how much product that you use.

James Watts
- Navarre, Florida

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