petroselinic acid separation?

[skunked_once]

I've been doing some online searching to find GC conditions to separate the methyl ester of petroselinic acid (6-octadecanoic acid) but no luck so far. It's an isomer of oleic acid and they coelute using the GC conditions I am currently using. If anyone has the details, please reply. In the meantime, the search continues!

[Bruce Hamilton]

I once ( 1990s) separated these on a standard polar capillary using a protocol than involved making the butyl? esters rather than methyl esters.

There's quite a lot of literature about separating the various C18:1 forms, and a FAME application used be in the J&W or Supelco catalogues for a long 50+m polar column. Try searching on C18 positional isomers + FAME + GC. I believe you will struggle if the two peak ratios are not similar, as there is not much difference.

If you need more info, I can try and dig it out.., meanwhile as usual, read...
http://www.lipidlibrary.co.uk/topics/altester/index.htm

Bruce Hamilton

[skunked_once]

Bruce,

Thanks for the suggestions. I've found some useful references so now it's a matter of sorting out the information. Looks like I may need to but a 100 meter column.