Chromatography Forum

My detector signal has suddenly dropped with a factor of 4. Could this be caused by the lack of make-up gas (e.g. nitrogen) for the detector? The retention-times havent changed.

My detector signal has suddenly dropped with a factor of 4. Could this be caused by the lack of make-up gas (e.g. nitrogen) for the detector? The retention-times havent changed.

Hello Martinz,

yes! Did You have a FID? If yes, You need make up gas because of the flame geometry AND the gas velocity from the jet into the flame.
A good make up gas for FID is N2 or Air. The flow is instrument depending and mostly between 25 and 45 ml/min.

He is for FIDs not a good choice.

rgds

Bernd

Thanks! turns out some #$%& let a valve open. lost a N2 bottle in less than a day.