NIST SRMs: Determination of the Validity Period

The National Institute of Standards and Technology (NIST) produces Standard Reference Materials (SRMs) of basically *anything*. That also means that things like peanut butter are among those SRMs. SRMs come with a Certificate of Analysis (CoA) and have a validity period attached.


Given that NIST makes sure to know almost everything about their SRMs, how do they determine the validity period? Complex matrices can have difficult to estimate long-term influences on all the compounds in the sample. If they are running stability studies, when do they start those and for how long do they run?


