Clean the bore of the ion transfer tube to remove blockages caused by buffer salts or high concentrations of sample.

If pressure in the ion transfer tube and RF lens region (as measured by the Source Pressure gauge) drops below 1 Torr, the ion transfer tube may be blocked and need replacing. The normal source pressure reading is approximately 2–3 Torr. Replace the ion transfer tube if the cleaning procedure does not remove the blockage and the source pressure reading has not increased to the normal value.

Procedure

  1. Begin with Step 1 if there is extreme contamination. If not, begin with
    Step 2.
  2. Sonicate the ion transfer tube in a 10% solution of Liquinox in water for 60 minutes, then let it soak overnight.
  3. Rinse the ion transfer tube with water.
  4. Force a strong stream of water through the ion transfer tube's orifice for 2 minutes.
  5. Sonicate the ion transfer tube in water for 30 minutes.
  6. Sonicate the ion transfer tube in a 50:50 solution of methanol-water that contains 20% formic acid for 30 minutes.
  7. Rinse the ion transfer tube thoroughly with water.
  8. Sonicate the ion transfer tube in deionized water for 15 minutes.
  9. Rinse the ion transfer tube with methanol.
  10. Sonicate the ion transfer tube in methanol for 15 minutes.
  11. Dry the ion transfer tube thoroughly with nitrogen gas.