Chromatography Forum

Hello everyone, i'm trying to develop a method to quantify benzene in plastic (PET). I've found a method that use the same GC-MS headspace but they use an agitator 500rpm. i dont have an agitator, how can I resolve this?

Thanks in advance

You're analyzing solid PET? If yes, I'm puzzled as to why anyone would agitate a solid in the first place. Stirring gas is kind of pointless as diffusion in the gas phase is very, very fast.

To me, the key is to get the plastic above the glass transition temperature. In that situation, your solid material will behave more like a liquid. 90 °C or so should do it for PET. The rate limiting step will be equilibrating the solid with the gas phase in the vial.

I saw an application note by PerkinElmer not long ago on this. I think it's available on their website. They heated the sample to 200 °C (or something like that) but from the text, it was not clear why they chose that temperature. Seems a little hot to me but I guess it worked. I don't recall them agitating the sample.

You could also try leaching it out in a 50% IPA:water mixture then running the leachate on a purge and trap instrument.