FIA chromatograms show signal suppressions

FIA chromatograms show signal suppressions

If the FIA chromatograms show signal suppressions, it is most likely either caused by the injection system or by an issue at the ion source.

To solve this issue, check the following parts at the LC-MS system:

  1. Inspect the ESI electrode and its connection parts for any small leakage or blockage
  2. Check for leakage or blockage at the last valve or grounding before the ESI electrode (if applicable).
  3. Examine the ESI electrode for any issues. Clean or replace it if necessary.
  4. Inspect the needle seal or seat for signs of wear and replace it if outdated.
  5. Ensure the syringe is not drawing air, as worn plungers may cause this issue.
  6. Check for air inside the syringe pump and flush if needed.
  7. Thoroughly clean the injection valve.
  8. Perform the SST again by conducting test sample/test mix FIA injections using the FIA1 method (if applicable).