Chromatography Forum

Hello,

This is my first forum post. I did search the forums for help on this topic but found nothing.

We have a HP 6890 system, which I have *some* experience with, but still have lots to learn. I recently cleaned the FID jet and reinstalled it (this also included trimming the column below). After booting up the system, it is telling me that the front detector output is 0.0 which tells me that there is a problem with the carrier gas getting through to the end. I have tried 'readjusting' everything that I had touched during the cleaning of the jet. Still no luck.

Does anybody have any insight into this problem? Thank you in advance,

We have a HP 6890 system, which I have *some* experience with, but still have lots to learn. I recently cleaned the FID jet and reinstalled it (this also included trimming the column below). After booting up the system, it is telling me that the front detector output is 0.0

That would direct me to make sure that the front buttons/software are set for "Detector On". Or that your flame is not lit. Or that you have aligned the detector command with the signal.

it is telling me that the front detector output is 0.0 which tells me that there is a problem with the carrier gas getting through to the end.

If you disconnect the detector end of the column and hold that end under methanol in a small beaker, you should see carrier gas exiting if there is flow getting through. Re-install by inserting into the FID until it touches (maybe 4 inches) then pulling back like 2 mm, then tightening.

We have a HP 6890 system, which I have *some* experience with, but still have lots to learn. I recently cleaned the FID jet and reinstalled it (this also included trimming the column below). After booting up the system, it is telling me that the front detector output is 0.0

That would direct me to make sure that the front buttons/software are set for "Detector On". Or that your flame is not lit. Or that you have aligned the detector command with the signal.

it is telling me that the front detector output is 0.0 which tells me that there is a problem with the carrier gas getting through to the end.

If you disconnect the detector end of the column and hold that end under methanol in a small beaker, you should see carrier gas exiting if there is flow getting through. Re-install by inserting into the FID until it touches (maybe 4 inches) then pulling back like 2 mm, then tightening.

Thank you for your reply! With regards to your first response, does the flame need to be lit in order for the output to have a reading (other than 0.0)? I thought the flame would light after I verify the output is working correctly. Maybe that is my problem.

..., does the flame need to be lit in order for the output to have a reading (other than 0.0)?...

The flame has to be lit and the electrometer must be on.

..., does the flame need to be lit in order for the output to have a reading (other than 0.0)?...

The flame has to be lit and the electrometer must be on.

Got it. Thank you for the reply. Once I lit the flame everything worked nicely. Much appreciated.

For future reference - it's not a bad idea to keep a small mirror around. Holding one at an angle over the FID can tell you whether it is lit, either by allowing you to see a glow directly or by having a bit of condensation appear on it.

... Holding one at an angle over the FID can tell you whether it is lit, either by allowing you to see a glow directly ...

Can your eyes see UV radiation ?

I don't neglect. In fact, when you switch off the light and the room is dark, ... and your eyes are accomodated to darkness hydrogen flame will be visible.

Or you meant ignition filament glowing.

I believe DR means look for condensation of the moisture from the hydrogen combustion on the little mirror. Or do similar using a shiny piece of metal, like a chrome-plated open-end wrench.

I believe DR means look for condensation of the moisture from the hydrogen combustion on the little mirror. Or do similar using a shiny piece of metal, like a chrome-plated open-end wrench.

I am even convinced that DR means a condensation on the mirror - this is his second purpose of having mirror handy.

But cit. "allowing you to see a glow directly" as a way of finding out whether FID is lit makes me curious.