Hi Efosa,

There are several methods you can apply for this purpose. I will menthion the two methods I usually use to remove hexane after fatty acid extractions:

-Vacuum rotatory evaporation: using vacuum and a temperature around 40C you will be able to remove all hexane in a short time. Using this method you can recover the hexane since is a kind of distillation method.

-Heating block under nitrogen stream. I usually employ 40-50 degrees, but depending on how sensible your extract is to temperature you may choose another temperature. If you are doing that, use always a fume hood.

I hope it is helpfull for you

Regards

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Hi Efosa

Carlos' methods are both suitable but keep in mind that hexane extracts the non-polar compounds and as such, depending on the plant, you may have a lot of essential oils and lipids in your extract. these may be lost or will not miscible in water. I suggest using another solvent, such as dimethyl sulfoxide, depending on what you plan to do with your extract.  

Thanks for the answers. Will give it a try.

n-hexane extracts the fatty acids, lipids, and small molecular weight compounds predominantly from the plants. type of evaporation depends on the type of the plant material and kind of chemical compounds we are looking for in it. primarily i suggest for open air evaporation in shadows as to eliminate the doubt of loss of compounds. the dried consistancy will not be achieving for the extract if more of resinous matter exists in the extract. so it remains as semi solid.  if volatile substances are doubted the plant should be subjected to oil extraction before n-hexane extraction. this extract will not be water soluble. so we need to add some emulsifying agent like natural gums to make a solution to be administered to the animals for activity screeninig. plz fell free to contact for more info.

Thank you.

I am actually interested in extracting phytochemicals not soluble in polar solvents but in non polar solvents like hexane. Not interested in fatty acids and lipids and I desire to obtain a dried extract free of solvent so it could be stored for a very long time..Please i need more answers.

Thank you all for your answers so far

Hexane extract is best dried in a rotary evaporator under vacuum and without heat (SpeedVac - a centrifuge attached to vacuum pump). Dried extract should be dissolved in a nonpolar solvent with antioxidant added (BHT, pyrogallol), it will not be soluble in water (your original question). Dried extract free of solvent will not be stable even in freezer, unless sealed under vacuum. When solubilized, it will be stable at -80C for a long time, maybe a few months at -20C (flush the headspace with nitrogen). The freeze must be laboratory type, without light inside to prevent explosion. Fatty acids may be removed from hexane extract by saponification of triglycerides and subsequent water extraction. Sterols may be partially removed by freezing out from solvent. 

Thank you