Warning: calibrated compound not found (GC-7890b)

Verify the signal you are collecting is the signal in your calibration. I.e. you may be seeing signal A in the real time window, collecting signal A but calibrated with signal B.

Hi Milad,

Your problem is very strange.  What version of OpenLab are you using?  Is this the only method this happens with?

Could you attach the method and data files?  It would be very helpful if I could take a close look at both.

Tim

Hi Milad,

I looked at the method and data files and don't see anything wrong with them.  It is a bit unusual that you have the front detector listed as signal 2 and the back detector as signal 1 but there is no reason you can't specify it that way.

Since you are using a headspace there are all sorts of things that can cause no peaks (plugged lines / leaking lines / bad valves).  Can you confirm that you see peaks for the signals on the "Online Plot".  The data files look very much like blanks.

Tim

Hi Milad,

Is this a factory-tested analyzer?  The naming convention of the method is similar to a targeted analyzer that shipped with a factory tested method.  I'm guessing maybe for Greenhouse Gases?  From time to time, the valve timings and flows need to be verified due to column age and other variables.   

These systems have an adjustable needle valve just outside the valve box that can be sensitive to bumps.  I recommend following the setup instructions in the manual to measure flows in multiple valve positions and re-establishing the valve timings.  The manual ships on a CD-ROM with the valve diagram, checkout method, data, and other system-specific details.  Often, the service person performing the installation will put a copy on the PC for easy access. 

Also, double-check the method setpoints to verify none of the pressure sources have been accidentally turned off.  Also check your valve actuator air and verify the valves are actually firing during the injection and throughout the run.  Leaks or plugs are always a possibility.  This system probably has a headspace, so plugged probes are common along with leaks around the transfer line.  Running the headspace leak and restriction test from the headspace front panel will help you troubleshoot the headspace independent of the GC. 

There is a possibility the column(s) need to be replaced as well. 

Keep us posted!

Abbey

When u check the scale of the succesfull run its quiete different from the one u don't see any signal at all.

The second one is either a blank, or the compound didn't reach the detector.

I once had the problem that I selected the wrong detector at the end.

Verify what signal you are saving....Detector 1 is being saved as Signal A....This is under the instrument conditions tab that follows the detector temp and flow settings (I am away from the lab right now, so I can't look at ChemStation). If you look at your calibration table, it should say signal A or signal B in one of the columns. You may need to change the Calibration table view to see this column. There are several different calibration table views.

Alternatively, "EDIT Entire Method"  You will reach a window that asks what signal will be used for calibration...You can change it here as well. 

If you look at the Real Time window, top left corner, you can see if this is signal A or B that you are viewing in real time.