# 10 w/v potassium iodede solution always gives the dark red color in aqua regia test solution.



## Quwannar (May 27, 2017)

Hi Dear friends;
I am trying to make a quick assay of gold and platinum ore samples. When I drop the potassium iodide to test the platinum and paladdium in every batch of aqua regia solution, color suddenly is turning to dark red rose and wine color. 
Some sources say that sulphide and other impurities can give the dark red rose color for false reading. However, when preparing hot aqua regia solution in process, Must sulphides be fully evoparated in boiling processs ? Must'nt it? In accepted protocol to test platinum or palladium as it is mostly known; 
- Take 20 drop Agua regia test solution 
- Boil over lamp flame until it is dry (fully evoparate platinum salt participate)
- after cooling, add 4 cc deoinized water and boil gently again and filter solution in another beaker
- add one drop potassium iodide and keep warm the solution and watch color change if it is red rose color that means platinum or palladium presense. 
In some internet videos, potassium iodide is directly added into aqua regia. 
I am so confused that
Especially in gold spot testing is very easy. But why platinum test method is so complex?
What are other impurities or metals in which give the red rose color with potassium iode?
Any comments would be appreciated.


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## Lino1406 (May 27, 2017)

What you get is free iodine


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## Lou (May 27, 2017)

You are adding iodide to aqua regia...what else can be expected?


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