serum vials for gas sample collection and analysis

[www_ups]

I need to collect small amts of gas samples from a reactor and analyze them in a Shimadzu GC-FID. I have used tedlar gas sampling bags in the past, but they are simply too big; I am looking at sample volumes of ~1-10 cc per analysis.

I have come across gas sampling serum vials (used primarily in microbiology and biogeochemistry) to collect small amts of gases. This link is one of many
http://rydberg.biology.colostate.edu/~j ... _vials.htm

Does anyone in this forum have experience in doing this kind of stuff ? what is the quality of serum vials (and septa) that can be used for this purpose ? Is a normal vacuum pump ok ?

Thanks,
Pradeep

[Peter Apps]

Hi Pradeep

I would advise againbst using serum vials - the septa are not designed for GC work, and will bleed volatiles into your samples.

Rather use GC headspace vials - these also have septum caps but they are designed for GC and will have low bleed.

Peter

[www_ups]

hi Peter,
Thank you very much for the suggestion. Could you kindly also tell me if this could be used to analyze just gases ? (i.e., my samples are gaseous & so i dont have a liquid phase.) can i evacuate the vial too ? lastly, can i inject gases into a evacuated head space vial without appreciable bleed?
thanks,
pradeep

Hi Pradeep

I would advise againbst using serum vials - the septa are not designed for GC work, and will bleed volatiles into your samples.

Rather use GC headspace vials - these also have septum caps but they are designed for GC and will have low bleed.

Peter

[Peter Apps]

Hi Pradeep

If you only want to analyse gasses i.e. carbon dioxide, oxygen, hydrogen etc etc than a serum vial will probably be OK - the septum will bleed organic volatiles that might not interfere with the gas analysis.

A GC headspace vial is very similar to a serum vial, and has the same crimp cap with rubber septum, but the rubber is designed to tolerate higher temperatures. What you can do with a serum vial in terms of evacuation and filling you will be able to do with a headspace vial.

If you already have serum vials, try them first before you spend money on headsapce vials.

Regards Peter