[fiskmaas]

Hi All,

I've hit a snag in a procedure and wanted to know what everyone here thought:

My procedure: Basically taking water from a hydrodistillation of pine needles and I want to get the various non-polar/slightly polar molecules out. I'm working on a smaller scale, so I can't slough off the oil fraction, so I've been extracting with n-hexane (industry standard).

My problem: I've been using a teflon stopper for my seperatory flask, however The stopper was stolen a few weeks ago, and my PI wants me to find an alternative instead of buying it (we have very little money). I've been racking my brain trying to find something, but I can't find anything that addresses the role of the stopper in the experiment. Black rubber stoppers get dissolved by the hexane and contaminate the sample.

Are there any alternatives that I can use, or should I just ask for another teflon stopper?

Thanks,

[g-bones]

glass stopper?

[fiskmaas]

I tried a glass stopper, but the hexane was leaking, and when I used grease, the hexane dissolved the grease and contaminated my sample.

I also have to perform GC on the components that I'm extracting. Maybe a teflon stopper is the best way to go.

[Borek]

Glass stopper with a teflon tape? Teflon tape is rather cheap and shouldn't be difficult to buy, it is used by plumbers. Check hardware store or similar place.

[fledarmus]

Do you have any other container which does have a good stopper? Sep funnels are convenient because you can turn them over and open the valve to reduce pressure buildups, but they are really only critical for draining one layer without draining the other. You can just put your mixture in a round-bottom flask or a bottle, shake it up with frequent venting, then pour it back into the sep funnel to separate.