12 Replies Latest reply on May 18, 2017 12:07 PM by whboyd3

    Sequence run on a 6890 with a G2613A tower.

    instrumentspecialist

      The first injection of the sequence will complete normally but on the second injection in the run, the vial is picked up and moved to the tower normally yet no injection occurs.  The fault light does not come on and the run time will continue until the sequence is aborted.  Tried Run Method several times and each injection was completed.  What could be the possible cause?   Thank-you.

        • Re: Sequence run on a 6890 with a G2613A tower.
          valentinrusu

          A lot depends on what software and revision you're using and whether you're using a sample tray (G2614A most likely) or a high density turret in the injection tower (8 sample locations in addition to the Wash and Solvent positions on the turret).

           

          Click Help > About to find out the software name and revision.

           

          I'll venture a guess, however. Run method implies a single injection, whereas Run Sequence should be used, using the correct vial locations depending on how many towers you have and the locations of the towers (front or back inlet). For an injection tower located on the front inlet, and without using a sample tray (G2614A most likely), the accepted vial locations are 101-103 for the standard, 3 sample-location turret, or 101-108 for the high density, 8-sample location turret. Similarly, for a back inlet installed injection tower, the valid locations would be 201-203 or 201-208. If a sample tray is being used, the accepted vial locations are 1-100 for the G2614A. Whichever of these configurations you're using, the vial locations from which you'd like to sample should be entered correctly into the sample sequence.

           

          Questions for you:

          1. What software and revision are you using?

          2. What is the Injection Location set to (typically under the Instrument menu)? In the same screen, is the method set for front injector, back injector, or both? Screenshots might help here.

          3. Does the sequence reflect sample locations in the correct (front or back) injector position and does it call for valid sample locations? A screenshot of the sequence table would help here, as well.

            • Re: Sequence run on a 6890 with a G2613A tower.
              instrumentspecialist

              Thank-you for the quick reply.

              I am using a sample tray and the correct vial (e.g. 1)is picked up in the tray and placed in the sample turret of the tower, at which point (on the second injection of a run), nothing happens.  The answers to your questions are:

              1.  ChemStation rev. C.01.05

              2.  Back injector location and method is set up for back injector.

              3.  Yes.

              If the above were the issue, would I be able to get the first injection of a run sequence to work correctly?

            • Re: Sequence run on a 6890 with a G2613A tower.
              valentinrusu

              Is the second injection from the same vial? What's the runtime of method and does it have a pre-run equilibration time? Is the method in the second line of the sequence table the same method as the one in the first line? A screenshot of the sequence table would help. Ultimately, there might be something wrong with the method and/or the sequence.

               

              Here's one quick way to troubleshoot this (or at least find a workaround):

              1. Create another method from the default (load DEF_GC.M, then click Method > Save Method As... and use a unique name like Test.M) with a very short runtime (0.1 minutes) and isothermal oven (whatever temperature the oven is right now).

              2. Put a vial with nothing in it in the sampler tray, and do a single injection.

              3. If everything proceeds correctly, create a brand new sequence from the default sequence (load DEF_GC.S, then click Sequence > Save Sequence Template As... and use a unique name like Test.S), then put the method created in step 1 and set the Inj/Location line to 3.

              4. Start this new test sequence and see if it goes from injection 1 to 2. Obviously, the tray would pick up the same empty vial, but if the second and third injections proceed successfully and you end up with 3 distinct .D files, then you'll know that both the hardware and software are working well, so the problem or issue would be with either your method or your sequence.

               

              If this all works, then building both the method and the sequence from scratch will not only be a troubleshooting step, but may turn into your solution.