Question

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?

Answer 1

The NIST establishes the validity period for SRMs through extensive stability studies and quality control tests, using internal standards to ensure consistent and reliable results. These studies begin prior to the material’s release and cover its anticipated shelf life.

Step-by-step explanation:

The National Institute of Standards and Technology (NIST) establishes the validity period for Standard Reference Materials (SRMs) through thorough stability studies and quality control assessments. The process to determine the validity period includes pre-clinical and clinical development stages where integrity and stability of the materials are rigorously tested.

An important aspect of this process is the implementation of an internal standard (IS) to ensure the reliability of analyte quantification during these tests. Stability evaluation is critical and requires validating the material under various conditions to identify any potential alterations in composition or degradation over time.

Stability studies are initiated before the SRM is released and continue for the duration that sufficiently covers the expected shelf life and use of the material. The time frame for these studies can vary depending on the complexity of the matrix and the nature of the compounds present.

Quality control (QC) samples, which are representative of the future real samples, are analyzed to estimate the parameters essential for the valid use of the SRMs. When an isotope-labeled derivative of the parent compound is not available for use as an IS, a structurally similar compound with identical behavior during the bioanalytical protocol is chosen.