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[SoulGrower]

I just found where the recommended storage (by NW on another thread), is in an envelope in the fridge.  Well, mines been sitting on a bookshelf for about 6 months or so.  But apparently it is somewhat hydrophillic (despite not dissolving in water easily).  It is now exactly like a bag of brown sugar.

Looks like its even turned a shade or two darker (can't remember if it was white originally but now it's tan). 

Can I still use this?  I guess if I weigh it out though, it's gonna be off bc it clearly has some water weight now.  Or would this be negligible?

[Auxin]

Yup, you can still use it.

I store mine [98% GA3] in a tightly sealed bottle out of the light at room temperature. I bought it in 1998 and its still a free flowing white powder.
In solution or with a buffer mixed in it will be more sensitive.

[SoulGrower]

Well, I weighed out 50mg of GA3 to dissolve in 50ml of h2o (1000ppm target).

Unfortunately, this is my first attempt using ga3, so I didn't know exactly what to expect.  Measuring out the ga3 was more like, ehem, weighing something you have to divide with a razor, cc, etc..  It didn't scoop out.

And it didn't readily dissolve in alcohol.  In fact, it took alot of coaxing with a toothpic and even a hot water bath.

I used ro water which measured 4 with my tds meter.  After adding the ga3 solution, and allowing some time for alcohol to evap, it measured 150.  I know its not measuring ppm but wonder if there is any correlation.  Of course I could still smell a bit of alcohol and I have no idea what affect that would have on tds reading...

Considering this was for some hard to get, hard to germ seeds, I'm not gonna chance it.  Just gonna order some fresh ga3.

[LIBERTYNY]

 My understanding is GA3 is susposto have a 'shelf life' of 2 years

 Im sure their is stuff you can do to extend that shelf life, But otherwise its cheap why risk anything ?

[Auxin]

'Shelf lives' are usually fictional.
I once caught my mom throwing away a jar of salt because it had expired, lol, I tried to explain that its shelf life is over a billion years but she didnt get it- the bottle said 2 years and bottles have authority! 

Some of my chems are things my grandpa bought in 1951, still perfectly good. Always be wary of shelf life labels on pure compounds.

2 Likes plantlight and nikshaz like this.

[Solipsis]

Eh shelf lives are not fictional, you mean perhaps that it is true for most medications in the form of preparations like tablets in packaging?

Pure chemical compounds can quite often oxidize or hydrolyze, but of course not always.

As a general rule, keep chems away from moisture, oxygen (air), warmth (also especially temp fluctuations) and sometimes also light (usually its the UV light that is harmful, hence amber glass).
When you refrigerate or freeze it is that much more important that you have a hermetic seal otherwise condensation can be a serious problem, sometimes even for compounds which aren't hygroscopic.

[Auxin]

I did say 'usually fictional'.
Aspirin not sealed very well will decompose over time (thats why aspirin often smells like vinegar) and your right about UV, especially in the case of GA3. GA3 is rapidly destroyed by sunlight.
But most organic and, especially, inorganic compounds are extremely stable when stored properly.
Product manufacturers know that stating a shelf life is just an essentially free way to get people to buy more of a product. If the shelf life they state is actually based on probable real-world degradation of the product its usually on the assumption of below average or poor storage conditions.
For example, properly stored white rice was found to be perfectly edible after 20 years. A bag of rice might say 1 year.
Common sense should prevail.

[Solipsis]

Absolutely i agree

Probably a mix of selling more when you state a shelf life, combined with rules that you have to put something like that on a lot of consumable products, but also other factors like people don't think beer is fresh if you don't put like a shelf life of 6 months on there even though it's much longer.. plus we have to consider that there are some unreasonable quality standards wanting a product to be used when it is kinda perfect and pretending that it's no good when it deteriorates just a little. (Of course people are often obsessed with ideas about how things should be even though these ideas are not objective or justified at all)

Anyway yea these forces conspire to get these date stamps.

As I am finding is true with a lot of things, people generally have very limited understanding of the subtleties of chemistry and the mentality sensitive to 'cognitive ease' demands matters to be polarized so that we can all understand it and agree to form a consensus.
You just have to know which compounds are stable and which are not, and indeed expiration dates don't necessarily tell you anything.

Well back to the topic at hand: I do recall that certain plant hormones I work with are not stable in aqueous solution, and this is also relevant for those substances that can deteriorate like you say when you don't screw the cap back on well - they tend to oxidize or hydrolyze and I think the latter is true for aspirin.
That said, another trick of chemistry (or rather our kneejerk brains) is that we assume that an overt smell of vinegar indicates that the degradation of aspirin was significant, just like we assume when a chemical product is very discolored that the impurities in there must be in significant amounts, but this is often not true and very tiny amounts of certain heavily colored compounds can quickly discolor the overall appearance.

[Solipsis]

I made a concentrated solution of GA3 in ethanol (25 mg/ml) and keep it in the freezer.

This: https://www.sigmaaldrich.com/technical-documents/protocols/biology/growth-regulators.html

says GA3 can be stored as powder at room temp but if you make sure it is sealed airtight and enclose a desiccant you can probably make it last quite a while.

There should be no water in your solution ideally, otherwise IIRC you are supposed to use the solution within about 3 months and store it at 2-8C.