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Thermo Fisher Scientific

EMRS lots show 322 ion intensity lower than normal


Lower than normal intensity for the 322 ion which might cause certain calibration routines to fail or prevent them from being performed.


  • Mass Spectrometry
  • Some EMRS lots with expiration date of May 20-21, 2021
  • Some of the Lot numbers that have been reported having a low intensity for the 322 ion include VE300702, VE302063 and VG302357


Follow these steps if you encounter this issue.

  1. Infuse EMRS using the factory recommended source conditions, including source fragmentation parameters, and obtain a stable spray.
  2. Set the instrument to Full Scan mode (50 to 1650 amu) and verify that the intensity of any calibration ion is not below 100,000 counts (profile mode). The EMRS ions for positive ion mode are: 69, 102, 215, 622, 922 and 1522. The EMRS m/z ions for negative ion mode are: 69, 113, 302, 602, 1034 and 1634.
  3. Verify that the intensity of the 322 ion is not below 100,000 counts (profile mode).
  4. If the intensity of the 322 ion or any of the other calibration ion is lower than 100,000 counts, discard the EMRS solution and try a different lot.
  5. Do not attempt to run any service diagnostics or calibration using a bad EMRS solution.
  6. No Mass Spectrometer hardware should be replaced because of this issue.
  7. The supplier is already aware of the situation and are working on correcting this issue with upcoming lots.

Example of low intensity for 322 ion

low intensity for the 322 ion - image.png

Example showing good intensity for 322 ion

good intensity for the 322 ion - image.png



The 322 ion is not used for the normal Tune and Mass Calibration, Mass Calibration, Check Mass Calibration and EM Gain Calibration routines, therefore these calibration routines should not be impacted by this issue.

However, the 322 ion is used for some service diagnostics where minimum intensity levels are required. These diagnostics include: Drag Field Calibration, Asses Drag Field Calibration and Product Spectrum Evaluation.


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