Sciencemadness Discussion Board

Iodine tincture goes colourless/white?

Kashmeer - 9-12-2016 at 01:37

Hi guys,

I noticed when I mix iodine tincture (iodine and potassium iodide in 90% ethanol) with some cream (main ingredients list parabens, petroleum jelly and cetearyl alcohol) and zinc oxide, the cream goes from brown (tincture colour) to white after a few hours.

Any ideas where is the iodine escaping to?!

When tested for free iodine, the cream doesn't stain starchy material blue, so I am thinking iodine is not available any more?

aga - 9-12-2016 at 03:01

The iodine isn't escaping, it's just reacting with the 'cream'.

Depending on what ion is produced, it can even become completely colourless.

Tsjerk - 9-12-2016 at 03:15

My guess is that your iodine is reacting with unsaturated carbon species, so indeed the iodine is not available anymore and won't work anti-microbial anymore.

This reaction is actually used to determine the amount of unsaturated bonds in a compound.

[Edited on 9-12-2016 by Tsjerk]

MrHomeScientist - 9-12-2016 at 07:22

Just like it's not a good idea to mix bleach and ammonia hoping to make "super cleaner", it's probably not a good idea to mix medicines to make "super meds".