6 Replies Latest reply on Jul 31, 2018 7:21 AM by alejandro.ortegahern

    Method run failure


      Hello all,


      I am encountering a problem with my GC (7890B) QQQ (7000C). MassHunter Version 8


      This issue started around last week, and I restarted the computer (not the instruments) and the instrument starting functioning normally.


      The Problem:


      When loading a method, the two boxes in the left go from "pre-run" and "idle" to "ready" (as expected). Where the ALS should begin to purge and take a sample and inject, the method will switch from "pre-run" to "post-run" without injecting the sample or running the method. Last week I restarted the computer and this was sufficient to make the instrument go back to normal and run my samples.


      Today, however, this was not the case. The only difference this time is that the autosampler will move the vial and the syringe begins to purge itself with solvent and it fills itself with the sample and the stops. Once the syringe is filled with sample, the method switches from "pre-run" to "post-run" without injecting, thereby leaving the syringe filled with sample.


      My attempt to solve the problem:


      I restarted the computer, but this time nothing was solved. My next attempt involved turning both the GC and MS off, as well as restarting the computer and still the problem was unsolved.


      I am hoping someone can help me with this problem. I would be eternally grateful!



        • Re: Method run failure





          The flow and pressure of the column are not at the indicated setpoints. I am assuming this is why the method fails. I am unable to figure out how to change this. Does anyone know how to force the flow to follow the setpoint?

            • Re: Method run failure



              Before diving into troubleshooting a potential inlet over-pressure issue, let's doublecheck to make sure that is actually what is happening.


              Is the GC status not ready if you press the [Status] key on the front keypad? If it is Not Ready, it should provide you with information on what is preventing the GC from becoming ready (front inlet pressure, front inlet temperature, etc...).

                • Re: Method run failure

                  the status reads


                  ”No EMF from MS, not connected“


                  ”status-not ready

                  waiting for ready

                  host system not ready”


                  Does that mean anything to you?


                  Thanks so much

                    • Re: Method run failure



                      Scenario 1: when I switch the inlet to split mode, all the actual pressure, septum purge flow, and total flow meet the set point conditions.


                      Scenario 2: In splitless mode, the pressure, and septum purge flow meet the setpoint conditions, however, the total flow does not meet the set condition of 34.377 ml/min (instead it’s 18.14ml/min).


                      Scenario 3: When in pulsed splitless (this is the condition we use for our work), the actual pressure is 20 psi vs 13.55 psi, and the total flow is ~4 ml/min vs 34.377 ml/min.  The septum purge does meet the set point conditionof 3ml/min.


                      it should be noted we have an MMI inlet. Also, I changed the inlet and septum and am still encountering this problem.


                      I hope this helps. And thanks again.


                      My next idea is to maybe cut the column?


                      All suggestions are appreciated.