3 Replies Latest reply on Oct 12, 2017 4:52 AM by james_jenkins

    Split peaks in Autotune on 5975 MSD

    behringerd

      The autotune on my 5975 GC-MS has split peaks for m/z 69, 219, and 502.  The air and water background are <10%.  The source was recently cleaned. This instrument has been running tobacco extracts for about 4 years so it has been exposed to a lot of dirty matrix.  What could the problem be?

        • Re: Split peaks in Autotune on 5975 MSD
          james_jenkins

          Hi behringerd,

          Split peaks can happen for a number of reasons, vacuum, electronics, insulators, quad contacts. Any chance you could scan your tune report and we can have a look? Quite often this will give us a clue.

          James

            • Re: Split peaks in Autotune on 5975 MSD
              behringerd

              I have attached a copy of my tune.

                • Re: Split peaks in Autotune on 5975 MSD
                  james_jenkins

                  Hi behringerd,

                  Taking a look at the tune, there are a couple of things that are of note. You have a small leak with 7.52% N2 and 2.13 % O2. Minor leak but should be addressed . The most notable is the high repeller , its at maximum at 34.95. This typically indicates a dirty source, although where you just cleaned, could be the source insulators or the repeller as a cause. I would suggest replacing insulators and the repeller. You are also pushing a lot of column flow at 1.9ml/min (1.5ml/min or below would be preferred ) and that combined with the above can contribute to the splitting. Are you using H2 as a carrier as I see some water? If the above suggestions do not resolve the issue, I would suggest contacting your local service to set up a visit as there could be deeper issues with the electronics or the analyzer . Agilent | Contact Us

                  I have placed some part numbers below to eliminate the contributors to the split peaks.

                  2 ea Repeller Insulators G1099-20133

                  1 ea Lens Insulator G3170-20530

                  Depending on whether this is a stainless steel or inert source : SST G1099-20132 Repeller, Inert G2589-20044 Repeller

                   

                  The above are consumable items and should be replaced in the source at some maintenance frequency depending on the sample load and type of samples run. We do not have a recommended replacement interval because of the above reason. I hope this helps.