GC-FID - spikes in baseline

We have a GC-MA7890B with an FID detector and I are observing spikes in the baseline after we made a couple of changes.

We installed guard columns with unions on inlet and detector side, added a 2nd gas cylinder and required tubing, cleaned the FID detector and added a UPS to the computer next to the instrument.

When we saw the spikes we:

  • Checked all connections for leaks (snoop and leak check was fine)
  • We reinstalled new ferrules on both sides since the trim was found to not be good
  • We removed the 2nd cylinder and associated tubing (particles in tubing or gas supply?)
  • Removed guard columns and installed analytical column directly 

Thrse measures did not help.

We are planning to:

  • Install a deactivated fused silica column to see if the analytical column may be the issue (flaking of material)
  • Remove the UPS (electrical disturbance)
  • Checking FID detector again (loose electrical connection after putting it back together? Or introduction of debris when cleaning it?

Is there anything else you can think of that could cause these issues.

This is with guards

This is without guard columns, analytical column directly installed

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