C19:0 Elution

[afischer]

Hello,

I am trying to distinguish the 19:0 peak in a few standards I am running. Does anyone know the C19:0 can elute before C18:3n4, C18:3n3 and C18:4n3. Thanks

[skunked_once]

Andy,

I am running some FAME samples today and will have a possible answer for you this afternoon. I encourage others to respond also since there may be differences in results depending on GC conditions, column, etc.

[Radish]

It's been a few years, but I seem to recall that C19:0 does elute before the C18 unsaturates.

[mjfrayer]

What column are you using for this assay. I believe that the stationary phase does have some impact on elution order for this peaks.

Matt

[skunked_once]

Ta-dah!!! And now the results!

Analyzed on a 30 M J&W DB-23 column. (column and temperature program do affect elution order)

C18:3n6 cis-9,12,15 = 3.80 min.

C18:3n3 cis-6,9,12 = 3.55 min.

C19:0 = 3.54 min.

Definitive answer: maybe!

You need to run the actual standards on your GC using your analysis conditions to positively identify the peaks, and hope that there is no co-elution. Good luck!

[afischer]

Great thanks,

I am running an Omegawax 320. Running the Supelco 37 component mix and a sample with a 19:0 internal standard I got,

9.4 min - 19:0
9.6 min - C18:3n4
9.9 min - C18:3n3
10.4 min -C18:4n3