Elemental Phosphorus - 27-11-2019 at 14:25
I've been trying to use starch-iodide test strips to test concentrations of acetone peroxide in solutions intended to decompose it. The starch-iodide
strips clearly work, since touching them to the pure peroxide they turn dark immediately. After they go in the ammonia solution, even with peroxide
touching them, they don't react. I was wondering if ammonia in some way screws up the action of the starch-iodide strips. Thanks in advance for the
answers.
wg48temp9 - 28-11-2019 at 06:48
Iodine reacts with a solution of ammonia in water to form nitrogen triiodide. Perhaps that reaction interferes with your test paper reaction.
Pumukli - 28-11-2019 at 09:22
I think the formation of NI3 is a slow reaction while I2 and starch reacts quickly. So I'm surprised by your result but can't explain it. 
Ubya - 28-11-2019 at 11:55
the oxidation of iodide by peroxide works in acidic solution, maybe the ammonia makes the strips basic enough that peroxide doesn't oxidizes it
anymore
Elemental Phosphorus - 28-11-2019 at 14:26
I think Ubya must be right, I tried some strips in a concentrated sodium hydroxide solution and they wouldn’t react either.
Thanks for the replies.
Also, is there any other way to verify the decomposition of the peroxide? Does it shine under a UV light or some other form of illumination, or is
there a non-pH sensitive peroxide test? Maybe I’d be best off just visually verifying that no peroxide crystals are left.
Pumukli - 29-11-2019 at 03:03
Probably he is right. When I tried to use KI-starch a few weeks ago I used to detect hypochlorite. And hypochlorite works on KI even in basic
solution, hence my confusion.
Elemental Phosphorus - 11-12-2019 at 09:31
Speaking of all that, does anyone have access to this paper who can post a pdf?
https://onlinelibrary.wiley.com/doi/10.1111/j.1556-4029.2009...
Ubya - 11-12-2019 at 10:14
sci-hub.tw/10.1111/j.1556-4029.2009.01130.x