GC Shimadzu 2014 FID flame goes out after 30 min

[tdquadros]

Dear all,

I am facing some problems with the FID flame. I started working with chromatography 2 months ago, so I will try to explain the best I can the issue I am having.

I am performing online analysis of a stream containing N2, H2, O2, CH4, C2H4, C2H6, and CO2. They are the product of a combustion reaction, which I perform in a packed bed reactor. I have a condenser after the reactor to trap the water, and then I send it to GC. I am using a capillary column to run the analysis.

I started facing problems with the flame, always around 30 minutes after I start my analysis (each data point takes 25 minutes, which means the flame goes out in the second data point, around 8 minutes after the analysis starts). For the first data point, nothing goes into the detector (I get a clean baseline), for both detectors. In the second run, I have a small peak after 7 minutes (the peak from the GC valve working), and then the flame goes out.
This run (getting 2 data points) I did 4 times, always obtained the same result at the same time.

If I do not run analysis, and only load my analysis method, the flame will be on. I waited for approx. 2 hours without any change. The flame goes out only when I start analysis, and always in the second data point (I don't see any peak whatsoever in the first data point).

If any further information is required about the parameters I am using, please let me know.

Thank you all for your help!

[DR]

I suspect those who might be able to offer advice will want to know a lot more about your headspace settings...