Chromatography Forum

i am using Varian 450-GC with capillary Column, the problem is that there is flame out problem in FID but once the sample is injected it was ok but as soon as sample completes it gives warning of fleme out

Before you go any further you need to check whether the flame really is out, or whether it is burning but the electronics are giving a false error message. To check whether the flame is burning hold a shiny, cold metal or glass surface above the detector and look for condensation. If you see condensation the flame is burning.

If the flame is not burning then measure all the flow rates (with a separate flow meter not the readouts on the GC), including the carrier gas.

Check that you do not have a programme for the FID that might make it shut down at the end of a run.

How do you get it to be ready at the start of a run ?

Peter

after several attempts the Flame is on & ready for some seconds & we inject sample but it will also flame out during run but fortunately there r 6 minutes before first peak & it is not flame out till 35 minutes run

And the results of the tests and flow rate measurements are ...... ???????

there is no leakage i have changed the Burner tip but after that fid works well but my sample last peak is very large what is the reason while other peaks r normal plz help

Check the auto zero, Flame out is usually indicated when the background level when lit is below a certain threshold. This can occur if the GC will accept a negative value as zero when not lit. Are you flow programming ? increase of flow , decreases the baseline getting you below flame out threshold ?