Meet our techs: Sandra Nason

Sandra has been working for Thermo Fisher Scientific since 2007 and brings her expertise in electronics, production and testing towards quick and comprehensive solutions for our customers. 

Our techs are here to answer your questions, just email us.

Ask our techs ›

If you like this month's Q&A, check out our Talk Tech archive.


Ninety nine percent of the time when the mass verification is failing (result is >2.5%) the verification filter being used is the issue. When a weighted verification filter is not handled properly, it can forever after have an actual weight that differs from the weight listed in the kit. Some of the reasons the verification filters can expire are as follows:

  • Extended exposure to ambient air
  • Physical damage
  • Taking on particulates from a sample stream

Extended exposure to ambient conditions can cause the filter to soak up humidity from thin air. If the pre-filter is not used during the K0 verification or the smallest rips or tears in the filter paper can alter the weights of the verification filters.

Please see the TEOM KO Verification Kits  Technical Bulletin on proper handling procedures.

For replacement mass verification filters, use part numbers:



Mass Calibration Verification Kit (Incl. 1 Weighed Filter & Filter tool)



Refill for Mass Calibration Verification Kit (1 Weighed Filter)



Mass Calibration Verification Kit (Incl. 5 Weighed Filters & Filter tool)



Refill for Mass Calibration Verification Kit (5 Weighed Filters)

If the mass verification is still failing with a known good filter, please contact Technical Support at:

Telephone: 866-282-0430
International Telephone: 508-520-0430
Select menu option 2 for Technical Support

To order spare parts, call (866) 282-0430, option 1 or fill out the part request form for a quote.


Don't miss out. Subscribe today.

Talk Tech is published here every month. Receive our monthly Talk Tech answers delivered right to your inbox by subscribing using the button below.

Subscribe to Talk Tech ›