ASTM E 928 : 2025

1.1This test method describes the determination of purity of materials greater than 98.5 mol % purity using differential scanning calorimetry and the van’t Hoff equation.

1.2This test method is applicable to thermally stable compounds with well-defined melting temperatures (that is, not polymers).

1.3Determination of purity by this test method is only applicable when the impurity dissolves in the melt and is insoluble in the crystal.

1.4SI units are the standard. No other units of measurement are included in this standard.

1.5This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.6This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.