This Information Applies To:

  • 597x GC/MSD
  • MassHunter Software
  • MassHunter Software with MSD ChemStation DA
Procedure:
This procedure outlines how to troubleshoot 597x NCI tune problems using the MassHunter Software.

Note: This procedure will also work with MS Chemstation Software and the 5973 GC/MSD and GC/5975 MSD but manual tune windows will be different.

Steps:
  1. Does the PCI tune look good and do you have the correct ratios of masses 27/28 In your methane ions for PCI.  Is mass 19 greater that 10% of mass 17? Is there any mass 32 present?

  2. Make sure that PCI works before trying NCI. See the “PCI TUNE TROUBLESOOTING 597x Mass Hunter“ FAQ.

  3. Make sure that you have loaded the NCI tune file. Typical source settings and NCI tune file from the past that was a good tune. Simply click on the menu called “file” in your tune and vacuum window. Then click on the item named previous tune and select a good past PCI tune file and save it.

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    1. In tune and vacuum control click on the menu “parameters” then click on “manual tune” Make sure for NCI you have under the ci tab the Admit gas set to 40%. Now under profile tab set the ions for the NCI calibrate PFDTD ions are 185, 351, 449.



      Make sure your methane flow is set to 40%.



    2. If you have peaks even if they do not look as good as these, you can try to tune for NCI and see if the software will sharpen them up.

    • Possible contamination in NCI
      •

      Mass 235: rhenium oxide (usually a sign of a leak in the GCMS or CI flow module) 

      Mass 238: OFN in presence of oxygen or water, OFN loses CF2 (mass 50) and an oxygen molecule (mass 16) gets inserted 272-50+16=238. 

      Mass 254: OFN in presence of oxygen or water loses CF2 (mass 50) and two oxygen molecules (mass 16 x 2) get inserted 272-50+16+16=254.

      254 maybe an inlet leak, Column nut (inlet), Transfer line nut, Inlet Septum

    • List of Ions in PFDTD
      •

      The ones we use to tune: 185, 351, 449 

      The ones not used for tuning but are still present: 128, 129, 166, 228, 283, 517

      Typical lens ramps for NCI. These may vary somewhat on your system 



    If PCI looks good and you do not have any major contamination ions bigger than 10% of the OFN checkout ion 272.

    If this troubleshooting procedure does not resolve the issue, contact your local Agilent trained Service Engineer or submit a Support-Related Inquiry.