[imendeleevitsnotbutter]

Hi all,

When I go camping, I sometimes treat my drinking water with tetraglycine hydroperiodide, which gives it a nice brown color and a disgusting taste and kills nasty parasites. If I then put the water in my titanium cookpot, it turns dark purple! I have a friend with the same experience but I can't find anything about it online. My pot doesn't have a coating and the water doesn't have any additives so I'm pretty sure it's a reaction between the tetraglycine hydroperiodide and titanium. The only hint I can find is that titanium triiodide is purple, so I'm curious if this reaction is possible under standard conditions:

C₁₆H₄₂I₇N₈O₁₆ + Ti  -->  TiI₃  +

Or if you have any other idea why this might be happening, please let me know! I am really surprised at the lack of info since both of these products are commonly used by backpackers.

If you think you have an idea of what's happening, please tell me if the products are poisonous.

Thank you.

[Arkcon]

Well, here's a link to a common brand of water treatment for outdoors people:

http://www.pharmacalway.com/FAQ.html

On that page, they tell you that the compound won't stay in water, but instead rapidly becomes something else.  And you can complicate that further by other additions, like ascorbic acid. 

[imendeleevitsnotbutter]

Thanks for the info! I guess I should ask what reactions can occur between titanium and the compounds present once the tablet has dissolved, which that site says are I₂ and HIO.

Would ascorbic acid be present in spring water and snowmelt? I thought that untreated water was mostly just H₂O with some some metals and salts. I assumed that any reactive potential with those wouldn't be influenced by the presence of titanium, but I'm asking because I obviously don't know a lot about this stuff. I guess I could try with DI water to be sure.

[Arkcon]

Some kits have ascorbic acid (vitamin C) to remove the iodine taste.  The vit C makes the iodine inactive.  Some people just add Kool Ade to improve the flavor.