Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Fundamental Chemical Metrology



Metrology is a formalized process to understand, compare and standardize scientific measurement of physical properties.  Measured chemical quantities are typically relative amounts of substance (number of chemical entities, e.g., molecules, within a mass or volume) or mass fractions of substances in pure chemicals, mixtures and composites, and materials of natural origin. Instrumentation used to determine these quantities are not absolute and results are often only useful for practical decision-making when material-based standards exist as common points of reference and comparison. Metrologically sound chemical measurements have real and far-reaching implications for nearly all industries — from healthcare, pharmaceuticals and forensic investigation, to perpetual applications in chemical manufacturing, agriculture, and food sectors.

The Chemical Sciences Division (CSD) maintains core chemical metrology capabilities for organic, inorganic and gas substances that support our measurement services and products. The underlying principles of chemical metrology are comprised of three main areas: 1) validation of analytical methods and measurement procedures through the use of Certified Reference Materials (i.e., CRMs, SRMs), Reference Materials (RMs) and other Quality Control (QC) materials, 2) traceability of results through primary methods and standards to the International System of Units (SI), and 3) thorough assessment and expression of the uncertainty of measurement results. All these metrological functions are conducted within a NIST-wide Quality Management System that provides quality assurance and confidence in our services and products.

Created June 22, 2020, Updated August 17, 2020