High Baseline Generator VS Cylinder

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GasGen
GasGen's picture
High Baseline Generator VS Cylinder

We are using GC FID with N2 generator as make up gas. The issue with this is, when using generator the pA goes up to 100 and when we switch to N2 cylinders the pA drops to 30pA. The response is immediate after switching over from an N2 generator to N2 gas cylinder. What could cause this to happen? Is it the N2 gas purity or the hydrocarbon content?
 

Greg Pronger
Greg Pronger's picture
My first response with this

My first response with this type of problem is to call in the manufacturer; they must have some spec, and what you are describing, I would have trouble is within "spec" for the generator. With an FID, moisture, and air should be almost "invisible" to the flame, so that would tend to leave hydrocarbon. Do you have any line conditioners in between? If the manufacturer is no help, then I would look at purchasing indicating traps to sort out what is causing the problem.

GasGen
GasGen's picture
The specs in terms of flow,

The specs in terms of flow, pressure and purity is right. We suspect is the HC as well....Initially no line conditioners were installed. After the problem, we put in an Agilent universal trap after the generator. Immediately to pA drops to 40 pA but after a few days the pA went back up to 100 pA. It was thought that there were some contamination that quickly saturate the universal trap. But we are wondering what is it?