Chromatography Forum

I have an Agilent 7890A with two columns, detectors and inlets. We run Chemstation B.04.03. For as long as I can remember, the front detector signal was FID3 B and the rear detector signal name was FID1 B. There was a headspace unit connected to the rear inlet. Last week, we disconnected the headspace unit to do some work with direct injection on the rear column and this week reconnected the headspace unit.

Now all of the sudden, FID1 A is the from detector signal and FID3 A is the rear detector signal. So, all of our methods try to collect signal from the wrong column and all of our calibration tables are invalid. Any idea how to change this back to the way it was? or modify the calibration tables to use the new signal name?

Hello

Do as below:

1.Go to Method tab
2.Take "Edit Entire method"
3.Mark "data analysis"
4.In "Signal Details" window check signal details for FID (delete lines and add new with correct signal)

Regards

Tomasz Kubowicz

Thank you for your help. Your suggestion helped me figure out what had happened.

It finally dawned on me that the order of the detectors in the signals table determines the name of the signal (i.e. first row is FID1, second row is FID2, etc). When the GC was originally set up 10 years ago, the installer had put the rear detector in line 1 and the front detector in line 3 with diagnostics in the 2 and 4 lines. I don't know why but that was how it was set up. All our methods looked at FID3 for the front and FID1 for the back.

When I disconnected and reconnected the headspace unit, I had inadvertently changed the signals table so that I had the front FID on line one in the configuration. So it threw everything off. I fixed it and it seems to be working now.

Again, thanks for your help.