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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: Cantacoxinha on March 12, 2018, 06:32:07 AM

Title: GC of volatiles
Post by: Cantacoxinha on March 12, 2018, 06:32:07 AM

I'm trying to analyze volatile aroma compounds in a fatty sample (edible seeds) on GC-FID, a couple of esters in particular. Preparation of the sample involves finely crushing the seeds + extraction with pentane followed by filtration.

I have developed a method for GC-FID which gives nice peaks of standards and a good correlation, however, when I inject the extract, I get way too many peaks and a noise, proably because of a huge amount of extracted fat and other compounds. The sample even gets cloudy when stored in fridge.

The question is how might I extract or separate the aroma compounds (themselves quite lipophillic) from the fatty matrix, but without losing them? I was considering QuEChERS, but it's useful mostly for analytes very different from the fatty matrix., if I understood well.

Any idea on what could be done here?

No SPME is available in our lab, unfortunately.

Forgot to add: If I try to run SPE of the pentane extract, will it result in loss of volatiles and a wrong quantification later?

Or some other kind of extraction...

Or some kind of extract-preconcentration, but I don't know it rotavaping the extract is useful here, again because of the volatiles loss.. BTW sorry for way too many posts.

Title: Re: GC of volatiles
Post by: Elric82 on March 12, 2018, 06:24:50 PM

Maybe this might help: http://onlinelibrary.wiley.com/doi/10.1002/0471142913.fag0102s02/abstract

I would have thought such extractions were more effective with hexane.

Edit: that was supposed to be a link. Sorry, but I guess I don’t know how to post links on the forum just yet