GC column selection for plant FAMEs

[StevenA]

Hello,
I want to purchase an appropriate GC column for the GC-MS analysis of FAMEs from plant lipids. In the literature I read that for this purpose, the DB-23 column is frequently used. My questions:
1. Are there additional considerations in GC column selection for the use in a GC-MS setup (compared to FID)?
2. The articles do not state the dimensions of the column. There are 4 lenghts: 15, 20, 30 , 60 m. How to choose? The most critical separation I want to achieve is most likely of the 18:1n-7 and 18:1n-9 double bond positional isomers.
3. Are other columns preferred, and why?

Thanks very much,
Steven

[chromatographer1]

Determine if you want/need maximum separation of positional isomers, even cis/trans isomers, and the temperature limits you will require.

This is in addition to durability issues if money has a strong bearing on your choice.

Review the chromatograms of different column phases over the range of FAMEs you expect to cover.

Determine the length of column you require (time and resolution factors) as well as column capacity (ID and phase thickness). A new more polar phase which pulls double bond isomers further apart is based on an ionic liquid, from Supelco who has sold the standard column based on a cyano phase for decades.

In general bonded phase columns and columns with a low bleed phase (ionic liquids) have a longer lifetime and are less easily damaged.

In any case do not treat these polar phase columns as you would a durable bonded 5% phenyl methyl silicone phase columns.

good luck,

Rod