Sciencemadness Discussion Board

Storing Light sensitive chemicals

CHRIS25 - 28-7-2012 at 08:05

I will be getting some potassium ferricyanide and ammonium ferric citrate soon and obviously will need to store the resulting solutions that I make in light sensitive bottles.

At first thought I was simply going to store them in a dark brown bottle that had some supermarket stuff in it (well washed out of course), but on second thoughts, daft as this question may sound, would it be absolutely necessary to buy the chemistry bottles that are designed for this purpose as opposed to simply finding a dark brown jar? They will not be stored in a dark cupboard by the way, just a little light will hit the bottles, this is why I am asking.

I can only get them in sets of 10 for 22 euros from a local chemical supplier. so a small amount of cash that may be, But I need to save every penny for other items that are necessary, so every little saving helps.

Arthur Dent - 28-7-2012 at 08:14

Dark brown is dark brown. Any glass bottle with a proper cap will do. Of course, if you don't want your chems to escape, make sure it's a cap liner that will resist the oxidizing/corrosive fumes generated by your stuff. If you can't find corrosion-resistant caps, then the bottles/jars will be quite useless to you.

Even better would be dark red bottles, but they are quite rare. I've seen on occasions dark blue bottles and jars.

Robert

BromicAcid - 28-7-2012 at 09:16

Common, at least where I am, is to just wrap a regular bottle in aluminum foil. That is what we do at my work although the final product is re-packaged after the fact. It's funnier when someone is working with isocyanides and they have to wrap a whole 72 L setup in aluminum foil :)

CHRIS25 - 28-7-2012 at 12:44

Ok guys thankyou, yes I know a bit of a lame question, but had to be sure, always a nasty surprise turns up when you least expect something to be not quite right. Good tip about the foil, thanks.

kristofvagyok - 28-7-2012 at 13:40

Maybe I'm dumb, but in the lab, I have never ever seen that ferricyanides (potassium, ammonium ect.) would be stored in dark bottles, not even the solid and not even the solution.

Allyl bromide is in a dark bottle, aniline, cresol, phenylhydrazine and some other highly activated organics is in a dark bottle, because they can do funny things to light, but ferricyandes? Isn't that a bit too careful from nothing?

Also: if dark bottle is needed, then usually normal brown glass bottles are used, if there is a really sensitive stuff in the bottle then they use brown glass bottles coated with black polymers.

CHRIS25 - 28-7-2012 at 16:16

Quote: Originally posted by kristofvagyok  
Maybe I'm dumb, but in the lab, I have never ever seen that ferricyanides (potassium, ammonium ect.) would be stored in dark bottles, not even the solid and not even the solution.

polymers.

Hi there, Ok, when you mix the ammonium ferric citrate with the potassium ferricyanide, that is extremely sensitive to light. The solution is used to sensitise paper ready for printing by the sun (ultra violet light), otherwise known as a cyanotype photograph. Hope this clarifies things.

kristofvagyok - 29-7-2012 at 03:04

Quote: Originally posted by CHRIS25  

Hi there, Ok, when you mix the ammonium ferric citrate with the potassium ferricyanide, that is extremely sensitive to light. The solution is used to sensitise paper ready for printing by the sun (ultra violet light), otherwise known as a cyanotype photograph. Hope this clarifies things.

Sorry, my fault, I thought that you want to store the solutions separately, not mixed.

If the photographic solution is mixed, then I would suggest brown glass with a polymer coating (somekind of tape).

CHRIS25 - 29-7-2012 at 06:13

Thanks, Kristo.. So really black masking tape around a clear bottle would actually be enough?

kristofvagyok - 29-7-2012 at 09:05

Yes, that should be perfect.

Also a little additional info: normal borosilicate glass does not let UV light pass it, just quartz glass, plexy glass and some other special purpose glasses let it through. The brown glass will also stop the rest also and just a few, mainly reddish low energy photon passes it.

CHRIS25 - 29-7-2012 at 09:53

Krisof...just a quickie there, if you are knowledgeable in this area that is, between normal sodium silicate glass, plexi and perspex, which of these allows more UV to pass through, UVB or UVA together or apart does not matter really, no need for absolute perfection here though, I was just curious as to whether there was a difference.

kristofvagyok - 29-7-2012 at 10:26

UVA is not stopped by plexi, perspex just in max. 20%, normal borosilicate glass stops it in approx 70-90% depending to manufacturer.

UVB is stopped by borosilicate in +80%, perspex stops it partially, approx 30%.

It is suggested to put some UV dye in the glass, put it next to a UV lamp and watch how does it glow. Fluorescein is not good for this test, because it also glows from near UV lights.

CHRIS25 - 29-7-2012 at 13:15

Hi, Sorry, should have said that I was wanting the UVA/B and so am glad to have asked because that spares me the disappointment of getting perspex, I nearly did. So ordinary glass or Plexiglass then is what I need, as little hinderance as possible is what I am after. (nothing to do with the storing of the chemicals)

Thankyou for your input