About using heptane instead hexane

[Calcitrans]

Hi:

I am really starting to analyze Fatty acids by GC, the problem I have is that my samples are dissolved in hexane and the evaporation in our lab is very high even when we are at 22 •C. I was thinking on the possibility of using heptane (Chromasolv - HPLC) instead, for extracting the FAMEs after transmethylate them with HCl- methanol. Does anybody has experience using this solvent?

thanks for your help in advance

[chromatographer1]

No problem. Use octane, too.

best wishes,

Rod

[Don_Hilton]

The higher carbon number solvents will elute later in the GC run. If you are looking for the shorter chain acids in the fats, the slightly later eluting solvent could become an issue.

[chromatographer1]

If a polar column is being used (and it probably is) there won't be much of a problem.

Even if going to nonane.

But your point is well taken.

Rod

[jdezeeuw]

You indeed can use heptane/octane /isooctane. Make sure that injection temperature is high enough(225-250). Use wool in the liner at inejction position for good evaporation and for reproducibility.

[mattmullaney]

I agree with everyone else above, we experimented with hexane/heptane/isooctane, and decided to use heptane. Never were any difficulties...we eventually chose to use cold-on column injection, as an aside.