Trying to find a way to react bromide to get bromine in solution of chloride salts.

[westwoodft]

Hi all!  Thanks for the help!

I have a sample containing bromine, bromide, and chloride salts in solution with water.  I am trying to measure the absorbance of bromide with a photometer for an industrial application.  The bromine peak is at 235 nm and the bromide peak is at 214 nm.  I thought about automating the phenol red colorimetric method with a reagent system, but chloramine-T is pretty sensitive and would create a lot of waste.  I can measure bromine easily, but bromine overlaps with my bromide peak making it difficult to measure bromide.  I was thinking if I measure the concentration of bromine first, and then react bromide in such a way to make bromine, I can then measure bromine again and take the difference to get my resulting bromide concentration.  I've read that I can maybe use Potassium Bromate, but I'm not sure of the implications this will have on bromine and chloride salts in my sample.

Any ideas on what I can use to make this work or is this idea just too crazy to attempt?

Any ideas are welcome!

Edited November 9, 2018 by westwoodft

[chenbeier]

Add some chlorine or hypochlorite and convert all bromide to bromine.

[westwoodft]

Correct me if I'm wrong, but doesn't hypochlorite and bromide react to make hypobromite?  Maybe chlorine would work.  I'll need to do some more research.