HP 5890 getting an EPPA: SAFETY SHUTDOWN - WHY?

Discussions about GC and other "gas phase" separation techniques.

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We are trying to get an HP 5890 Series II GC with an HP 5972 Mass Spec running - it was donated to our college.

On power up, the GC gives an


We are pumping Nitrogen through the GC (He is too expensive).
We want this operational for use in Organic II labs to show how a GC can separate components in a mixture and the Mass Spec gives the approx Mw.

George Kenney
Eastern Florida State College
Melbourne, Fl
EPPA likely refers to the EPC (electronic pressure control) module that controls the inlet pressure. You probably have a leak there. I'd install a plug into the base of the inlet, then run try to intialize your method again to see if the pressure will hold. If the EPC won't hold pressure (i.e., keep a reliable flow on your column), then the instrument goes into a "non-self-destruct mode" and will shut itself down.

Keep in mind that Agilent defines "detectors" as the analog ones (FID's, PID's, FPD's, etc.). The MS is not a "detector" in the Agilent lingo. It's an instrument on its own in the Chemstation software.
Response is correct, if you have a leak the EPC will shut down. You'll need to do a pressure decay test on the inlet.
Also you have to make sure the inlet knows it is using the correct gas. There should be a setting to tell it if the carrier gas is N2, He, or H2. If it is set to H2 you will definitely get a EPP shutdown error if the inlet pressure can not be maintained. Also see what pressure you are setting the inlet to and if that pressure is being achieved. If it can't get to the set pressure it assumes there is a leak. If you have the inlet pressure set to 50psi and the pressure from the tank is 40psi, then it will automatically assume there is a leak.

With the 5972 MS you will want to be using a 0.25ID or 0.18ID capillary column to make sure the flow through the instrument is not too high. Those can only handle about 2ml/min Helium flow max, and probably similar flows of N2 or H2. Actually H2 will give a much higher reading on the vacuum gauge even at lower flows, but that is because the gauge is calibrated for N2.
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