I managed to get a liter of ACS n-heptane with 0.001% evap residue (according to the papers), would like to know how long can I store and use the solvent.

The bottle only states the date of fabrication (a year ago), and Google results show anything from indefinite to 2 years after opening.

I believe that "indefinite" would be the right answer here, since the solvent doesnt magically transform itself into other stuff, and that the x years numbers are just to accelerate sales, but I would like to verify that with the ones knowing

Stored properly (sealed tight, cool, dry, space), you'll probably use it before it expires. Oxidation is the main concern here if I'm not mistaken.

Also, I recommend performing your own evap test on what you presently have. Not all batches are exactly the same and contaminants can pop up.

One love

But how would I know if it expired?

I rechecked the label, and it actually says "Min. Shell Life: XXXX/XX/XX" (from around a year ago). Now I'm not quite sure if that's the date it was bottled and from which I should start counting the shelf life, or the date until it was supposed to be valid and they sent me some old expired shit they had forgotten in some warehouse for ages lol.

This was the last bottle that the provider had, which is the only place that has it nationwide, and its the only seemingly good (ACS grade of European manufacturing) solvent I managed to find (I already tested a number of others available here, and they all failed the evap test, none of them ACS grade :/, + none of them even remotely close to the price of this one lol). And the next batch will only arrive like in 6 months due to the logistics delays they are having now with their imports.

Good questions, and I wish I had a direct answer for you.

I did a little searching and hunting on your behalf. The specifics we're looking for seem to be a little hard to find.

I did come across information specifying the difference between shelf-life (how long it remains in its same format unopened) and expiration (date it will no longer be "effective" or begins to break down after opening).

If it says minimum shelf-life is the date from a year ago, you may still be good, since that should be the bear minimum of its shelf-life (it would be nice if they could give the max as well).

A PDF I found stated that the shelf-life for heptane stored in a steel container is 12 months. I am assuming that is the minimum. However, this MSDS sheet states that the shelf life is indefinite.

I'd say start by doing an evap test. If it doesn't evaporate clean, it may be due to it being passed its shelf-life, but regardless, you'll definitely know that you can't use it.

One love

Thanks, will perform an evap test then