RATA Challenges with Method 30B constraints- More
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•The Method 30B QA of the trap is very specific to the initial concentration values when choosing the sampling parameters.
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•If the concentration values shift from the initial, one cannot assume that the QA is valid. At lower concentrations, shifts have a larger impact on staying within the boundaries of the method QA limits.
•At concentrations just above 1.0 ug, paired train agreement can be challenging.
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Question:
   What does a stack tester tell a customer who wants the difference between the RM and CEM to be less than 0.2 ug?

   Answer:
   Stating that there is any significant difference between  1.0 ug RM and 1.2 ug CEM value implies an accuracy that does not exist.