• Created : 
  • Modified : 
  • Category :  Agilent Knowledge Portal
  • Entry Type :  Article
  • Product Type :  GC/MS Systems
  • Component :  GC/MS Single Quadrupole GC/MS Triple Quadrupole
  • Product Name :  5973 Series GC/MSD 5975 Series GC/MSD 5977 Series GC/MSD 7000 Series Triple Quadrupole GC/MS 7010 Series Triple Quadrupole GC/MS
  • Task :  Troubleshooting
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How to Blank off a GC/MS Instrument for Troubleshooting

Answer

This Information Applies To: Agilent single quadrupole and triple quadrupole GC/MS systems

Issue

During troubleshooting, it can be useful to isolate the MS detector from the rest of the GC system (sample introduction, inlet, column etc.).

Background

Blanking off the MS will help to determine if an issue is coming from the MS detector itself or the GC. Some examples where this procedure might be useful:

  • Noisy or unusual baseline.
  • Tuning difficulties.
  • Leaks (high oxygen and nitrogen on the tune report) where the common MS leak troubleshooting was not successful.
  • Large number of peaks in tune report.

Items Required

Steps to Follow

  1. Load the GC maintenance method. 

  2. Turn off the MS transfer line Aux heater, from the controlling GC/MS software or GC interface (keypad/touch screen)

  3. Vent the GC/MS system.

  4. Once the GC/MS is cool and vented, remove the column from the MS interface. Unscrew the column nut and carefully remove the column. It can be left in the oven, but be careful not to get the column end dirty or scratched. 

     

       Warning: Due to risk of explosion, when using hydrogen carrier, do not leave the column venting into the oven. Either cap the end of the column with a septum, or turn off the inlet pressure and leave the oven under 50 °C degrees Celsius.

     

  5. Install the no-hole ferrule into the MS column nut to create a blanking nut. Remember that the pointed side of the ferrule should face into the nut and the flat side of the ferrule faces towards the MS interface.

  6. Screw the blanking nut onto the MS interface.

    • For the regular column nut, screw on finger tight then us a spanner to tighten the nut an extra 1/4 to 1/2 turn. You will need to tighten slightly more after it has heated up.

    • For the Self Tightening column nut, screw in until it is finger tight (careful not to overtighten)

  7. Pump down the MS.

  8. After sufficient pump down time (and making sure that the new blanking nut is leak free), you can begin testing the MS:

    • Run an autotune. It may look slightly different (there is no column flow into the source) but assess if the issue is resolved.

    • If the issue occurred when an Acquisition Method was run, run a blank injection to see if the issues occur (except if you are using hydrogen carrier gas).

  9. Assess the results;

    • Is the issue still present? Then the problem is located to the MS, focus troubleshooting efforts there.

    • Is the issue no longer there? Then the GC system - column, CFT splitters or fittings, inlet, sample introduction, will likely be the source of the issue. 

 

 
Learn how to effectively operate and Maintain your Agilent GC/MS system: 
Agilent 5977 GC/MSD with MassHunter Workstation
Agilent 5977 GC/MSD with OpenLab CDS
Agilent 7000 or 7010 Triple Quadrupole GC/MS with MassHunter Workstation e-learning paths available from Agilent education

 

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