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Thermo Fisher Scientific

CAD OQ - Noise Test Failing


Trouble getting Noise test to pass for CAD qualification.


  • Qualification (OQ)
  • Corona Veo Charged Aerosol Detectors (CAD)
  • Vanquish CAD


Use better water for the test.

A highly pure water such as:

Fisher Plasma Water (1L): 080157

Plasma Water.png

Agilent Ultra Pure  Water for HPCE (500mL): THRAG-5062-857

Agilent THRAG-5062-8578.png


Can be ordered through Cloud 4 Service if the customer doesn't have suitable water on hand.



Using a higher quality of water can help achieve significantly better Noise and Drift values. Most laboratories do not have pure enough water for testing.

Also, always make sure the instrument has had a proper PM (if not new), and confirm no environmental factors (HVAC, for example) are not affecting the unit's operation as these can impact the drift test as well.


CAD instruments are highly sensitive to the quality of water, and require a higher purity than most LC detectors.


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