osmometry

https://doi.org/10.1351/goldbook.12238
Measurement of the osmotic pressure of a solution using an osmometer.
Note: The osmometry of a dilute solution of polymer is an absolute method for determining the number-average molar mass of the polymer and the osmotic virial coefficients of the solution.
Source:
PAC, 2015, 87, 71. (Definitions of terms relating to individual macromolecules, macromolecular assemblies, polymer solutions, and amorphous bulk polymers (IUPAC Recommendations 2014)) on page 92 [Terms] [Paper]