Chromatogram peak caused by rubber septa leaching plastics
Posted: Wed Dec 08, 2021 5:58 pm
We are using round bottom flasks to store bromofluoromethane and we put a white rubber septa on top to prevent the BFM from volatilizing and escaping. The septa are from VWR catalog 89097-556. We analyze the BFM using a GC-FID. After about 4 analysis runs, there is a peak that shows up late in the analysis run. I have analyzed a sample on a GCMS to try and identify what the peak is and the closest match was Butylated hydroxy toluene. I believe there are plasticizers leaching out from the white rubber septa while the BFM sits in the round bottom flasks. We have tried using glass stoppers before but they get stuck in the RBFs. My questions is what is the best way to try and mitigate the plasticizers from coming out of the rubber septa? I was thinking about soaking the septa in some dichloromethane and then baking it at about 110 C overnight.