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  for Metal Finishing since 1989
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Determining trivalent chromium conc. without oxidizing to hex?

I am studying the sorption of trivalent chromium.is their any spectrophotometric method available to determine its concentration without oxidizing to hex.

S Mustafa
peshawar university - Pakistan
2005

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When analysing Trivalent chromium by spectrophotometer, you will find a peak at 525-600 nm. This will enable you to detect the right concentration.
What is the solution you try to analyse? If you can give more info it will be easier for me to assist.
It is recommended to filter the solution prior to the test in spectrophotometer as turbidity affect the result.

Sara Michaeli
Tel-Aviv-Yafo, Israel
2005

I have lost my titration procedures for our FPL etch line. I am maintaining my etch line i.a.w. Mcdonnell Douglas DPS 9.34 Rev. P, table 3.1. I am using Turco 4215 as my cleaner and the acid etch is 15-17% by volume of Sulfuric Acid, 8-12 ounces per gallon of Sodium Dichromate and trivalent chromium content below 1.9% by weight. I must also maintain the Aluminum concentration above 0.2 ounces per gallon. I do not like to sound like an idiot but I am no chemist and I need step by step instructions and possibly a written standard that I reference in my procedure. YOu know how over regulated aviation is. I have to be able to prove everything. We had these steps written down on a piece of paper and now that paper is missing. I would greatly appreciate any and all help with this problem. Thank you all in advance.

Robert Neubauer
Aerospace Repair - Tulsa, Oklahoma
2005

The only way do comply with this is to get a a copy of the appropriate SOP for testing the tanks from the original manufacturer or from whoever might own them now.

James Watts
- Navarre, Florida
2005