A simple chemists question.....Iodine

[RAPPLEBY2000]

Hi i have a bottle of iodine bought in the last 5 years i have not used.

Does Iodine go out of date for water purification use?

also the bottle lid is broken not enough to loose the contents but enough to stain the label and everything else in the large container it was in an orangy brown .

is The Iodine still safe to use if it has been open to the air for goodness knows how many months or years? (the bottle still seems full).

 

[Schwert]

Iodine crystals I assume is what you have.

These consist of pure iodine (I2, two atoms of Iodine per molecule) and while they do sublime (form iodine gas) they should not degrade for water purification purposes.

The orange/brown stain across the label is from the iodine gas reacting with the paper. Iodine gas is very corrosive so you will want to replace that cap.

If the crystals are still free flowing and not clumped up from moisture I would not hesitate to use these for water purification purposes. Presumably you will be making an iodine saturated water solution (like Polar Pure) for water purification purposes so even if clumped up these would still work, but the clumping would indicate exposure to moisture as well as air.

I have used USP iodine that was ancient for making vials suitable for the Kahn-Vassher method of iodine treatment of water.

 

[KIMBOKO]

I think that its probably iodine in liquid form. Which I believe is iodine in alcohol, the only problem that I can see with it is that if the alcohol has evaporated or there has been some dilution of the liquid then the normal method of dosing by drops per litre maybe inaccurate.

 

[xairbourne]

just chuck it in the bin and buy a new one its only couple of quid not worth the risk.

 

[RAPPLEBY2000]

i have the liquid form,
with the pipette (or dropper) as part of the lid.
i didn't know it was corrosive!
cheers for the advice.

 

[shona]

Rappleby

Iodine doesn't go out of date and will still be suitable as a water purifier (you know that it doesn't kill everything though?) It is also useful as an aniseptic.

 

[ArkAngel]

I use the liquid form as well and mine has a use by date on it.
For the £1.50 i paid for it i wouldn't take the risk, bin it and cope with the expense every few years!

 

[Schwert]

An alcohol solution of Iodine with a leaking lid....I would bin that too. (I always wanted to use bin as a verb). This is likely to be fine to use but like Kimboko states the concentration is likely not as stated on the label.

Iodine is a halogen and it is very reactive. Fluorine, chlorine, bromine, iodine and astatine are all halogens. Their outer shells are lacking one electron so these easily form metal salts like sodium chloride, potassium iodide etc. Their reactivity is why they make good water purification chemicals. Fluorine gas is so reactive that it is used to etch glass (or silicon chips).

 

[william#]

just chuck it in the bin and buy a new one its only couple of quid not worth the risk.

completely agree

 

[sandsnakes]

If you are using iodiene to treat water. Do make sure that anyone who is drinking it is NOT on thyroid medication.

Iodine will affect the natural production of thyroid hormones and cause them all sorts of interesting problems... as well as screwing your week end.

Probably the best bet is a small silver colloid generator contact this chap

aim@new.co.za he makes a generator about the size of two match boxes.

S