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What is the best vessel/seal to extract in?

Bas Sarkin

Bas Sarkin

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What is the best vessel/seal to extract in?

There are three versions:
1) first acid, then base. Includes some kind off naphtha.
2) direct base. Includes naphtha.
3) naphtha only, for things like re-x

The ones I used where PET plastic, soda-lime (normal) glass, borosilicate (Pyrex) glass.

Then there is the seal. Sometimes it can/will touch (swirling), sometimes it wont (re-x).
Things I used for re-x are plastic foil, aluminium foil, lose glass covering.
Things I used for the base are twist on plastic screws, wide metal screws (with some rubbery foil that crumbles rather fast, yuk!), cork, glass on glass..

But its all a bit... hmmm...

What is the best fabric to contain, and the best fabric to seal?

It should be resistant to
1) acid, base, naphtha
2) neutral, base, naphtha
3) naphtha
or all three at once, if possible

It should resist heat and cold a bit (-30C -22F to 80C 176F so it can be heated in a warm water bath and frozen cold during crystallization)

The seal should not 'get into' the solution at all. Perhaps by creating an odd shape for the bottle (long neck? tilted neck?), so it can be swirled without the base touching the seal...

The best I can find at the moment seems to be this 500ml soda-lime bottle with soda-lime seal:
apothekersfles.png
But it is not 1000ml, and its not borosilicate, and a base will etch the glass over time, if I am not mistaken....?

What, would you say, is the best? And why?
 
I would say borosilicate glass is the best, but regular glass is not really much worse.

I think plastic and contact with plastic, especially if it’s polyethylene, as long as it’s short, is actually not really problematic. For many of us, naphtha also often comes in plastic bottles or maybe a can, but then you know for sure that the inside of the can has a polymer coating. So if something were to dissolve, then whatever dissolves into that naphtha is already there.

Does that mean you’re inhaling microplastics? Yes, probably, but you’re inhaling those anyway. Of course you don’t want to inhale more than necessary, but when you’re using glass bottles and limiting the use of plastics it’s pretty good.

Finally, there’s also the consideration that laboratory glassware is noticeable. If you ever get a visit from people with other ideas, then that might stand out. So what works best are apple juice bottles with a metal screw cap, they’re lined with polyethylene. And after one use, just throw them away and buy new apple juice😉. Or if you’re going fancy go for a media bottle, see picture, as they are very robust and are the safest option.
 

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Bas Sarkin said:
It should be resistant to
1) acid, base, naphtha
2) neutral, base, naphtha
3) naphtha
or all three at once, if possible
Click to expand...
That might be the part to focus on most. You can look up "chemical compatibility chart" for your materials. Nitrile rubber is compatible with naphtha and you can make your own gaskets out of sheets of it.

PTFE or teflon is another option that might be compatible with all. Probably isn't necessary to resist both acid and base - could just swap the cap or transfer to another container.
 
For acid/base or direct to base, I recommend a volumetric flask. This way, the NPS (unless it's DCM or chloroform or something) is completely "sandboxed" in the long, slender neck, and there's little chance of you sucking up base soup with your pipette.

For freeze precipitate, a glass dish with a plastic lock-top fits the bill.
 
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