Dear Patricia,

In that case keep your lipid extract in a glass vial in the refrigerator (-20C). Otherwise if you keep it on the bench in the eppendorf it will leach plasticizers into your extract or oxidize via sunlight exposure.

An alternative, you may dry your sample under a stream of nitrogen (caution: do this in the fumehood!), depending on the volume you have it will take you a few seconds or few minutes. 

Hope this helps,

Ana

I agree with Ana: sealed glass vials in the freezer, -80C better than -20C, but for not that long time -20C can be OK.

Keep and eye on the speed vac: it should be aimed for solvents (some are aimed for acids, and the plastic parts could not be solvent resistant). If using nitrogen (very convenient) I would advise you to do it with the help of a water bath, so that you can keep your samples at room temperature during solvent evaporation. If not, they will get too cold and it will take very long to evaporate (again, depending on the volume) 

Best way is to dry under a stream of nitrogen, reconstitute in chloroform:methanol (2:1) in a glass vial, flush with nitrogen, seal it tight and keep it refrigerated. 

Drying under nitrogen is a good option. If you have to transport (hours) to the lab with the speedvac, do it on dry ice, or at least on ice. If you haven't extracted your lipids already, maybe transport these on dry ice and extract where the speedvac is. 

I agree with above answers. Coming back to your basic questions, I confirm that under chloroform and cold, lipids are well preserved.

I agree with above answer. I want to add that you can keep it in - 20 after seeling the cap for long time knowing the exat amount of chloroform, then when you need to analyze evaporate under nitrogen to dryness then add similar amount of chloroform, votrex and go on with your analysis ( lipid will never evaporate ), unless your compound is enesitive to oxidation it doesnt matter the time you keep it in chloroform..

They can be stored n choloform for a long time at -20 C. In this case we add antioxidant solution (BHT) to the lipid extract as well. 

Dichloromethane is more stable than chloroform and just as effective. chloroform may decompose with time if it doesn't have enough stabilizer in it to form HCl and phosgene.

For short-term storage chloroform is fine. Keep in mind that chloroform can break down to acids. If your samples contain plasmalogens (alk-1-enyl ethers), which are very sensitive to acids, they can degrade especially if air is present. So always flush with either nitrogen or argon, which is heavier than nitrogen, so it is easier to maintain that environment when sealing the tubes.

It's better to dry down under inert gas and store in sealed glass vials at -80C.

The experts have already commented to lipids in chloroform. I can confirm their suggestions. I only want to add that a few hours in chloroform is absolutely no problem, and SpeedVac drying would also be o.k.. In principle, a potential chloroform effect, i.e., the effect of formed HCl, on lipids depends on the single types of lipids, and is a long-time process. Only if you were dealing with plasmalogen lipids (as mentioned by the experts), you should be cautious. Of course, you should always use fresh chloroform and not that of some bottles that have long stood on the bench. Good luck!

If your glycolipid is soluble in chloroform (some complicated gangliosides or globosides are not) then they will be absolutely fine in chloroform for some hours, even if the lipid solutions are at room temperature. In case they have polyunsaturated fatty acids or they are prone to aerial oxidation you can quickly (a couple of seconds) flush the tubes with nitrogen or argon before closing/sealing them.