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.

Molecular Mass Distribution Measurement by Mass Spectrometry



William E. Wallace, Charles M. Guttman


This NIST Recommended Practice Guide presents a method using mass spectrometry to make a quantitative determination of the molecular mass distribution of narrow polydispersity synthetic molecular materials. The main obstacle for converting an oligomer-resolved mass spectrum (MS) into a valid molecular mass distribution (MMD) is the systematic uncertainty in the ion intensity axis of the mass spectrum. This guide demonstrates how to make gravimetric mixtures of analytes having the same general chemistry but differing in molecular mass distribution to 1) ascertain if mass bias is present for a given set of measurement conditions, 2) create a calibration curve to properly convert the MS to a valid MMD, and 3) determine systematic uncertainties for the calibration curve when certain specific conditions are met.
Special Publication (NIST SP) - 960-21
Report Number


distribution, mass spectrometry, molecular solids, polymers, quantitation, standards


Wallace, W. and Guttman, C. (2010), Molecular Mass Distribution Measurement by Mass Spectrometry, Special Publication (NIST SP), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed May 19, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created May 19, 2010, Updated February 19, 2017