Hello
I'm working on a project which is contributed to the analysis of butter essence in flavor industry.
Generally i used to dilute my samples with solvents like acetonitrile, n-hexan and ethyl acetate as a preparation step for injecting them to the GC-MS.
By using above solvents i have to turn off the mass detector at initial minutes of analysis for preventation of detector saturation.
But in the case of butter essence, some important species go out from column close to the used solvent so i can't determine them.
I can't run headspace injection because the system is planned to work with a SHIMADZU AOC-20i.
Is there any solution for analysis of this kind of volatile samples?
Dear Mina,
you can try HS-SPME, I mean SPME in the headspace. If you don't have an autosampler for this purpose, you can use the manual SPME, collecting the volatile compounds on the surface of the proper fiber for a certain time (I'd try for 30 minutes, or maybe more if necessary). You need also to set the right temperature, normally you need to heat you sample in order to enrich the headspace (I usually use 40, up to 60°C), but you are working with butter, so you have to be careful to choose the right temperature.
No solvent is necessary with this method and SPME is quite easy to use!
Ciao
Dear Valentina
Thanks for your attention
My important problem is lack of facilities like hs-spme. I have to run my analysis by classic extraction system and classic preparation steps for injections.
I'm looking forward a gc-ms program or a suitable solvent to solve this. However i have studied many articles and found nothing.
Hi.
You can try "playing" with column type/temperature conditions/carrier flow to overcome your issues, however, people here will be able to provide more accurate advice if you state which compounds (at least chemical families) you are targeting. Another approach could be selecting ions characteristic of your compounds which are different from the ones originated by your solvent.
Cheers!
Dear mario
Thanks for your advice.
Important compounds are acetic acid, butyric acid and diacetyl, with changing column temperature program, so i could seperate butyric acid from solvents but acetic acid and diacetyl cant seperate from solvent peak.
I tested this way too: i fulfilled the sample vial with essence and then emptied the vial compeletly, after that i heated the vial until 50 C, and turn on the ms from the start of run, in this way i could see the absence compounds but other compounds didnt see in this way.
I dont have a procedure for detecting all together.
If you work with SPME, you only need to buy an SPME holder and fibers, then you system is complete and ready to work.
You have to consider that working with this method will save your column for a longer time and no solvent will be necessary, so after some time you will spare some money and also a lot of time. However, it is not completely unexpensive, since fibers and SPME holder cost.
Nevertheless, if you can not afford it, you could inject the headspace manually.
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