ASTM E928-08(2014)
Standard Test Method for Purity by Differential Scanning Calorimetry
- Standard No.
- ASTM E928-08(2014)
- Release Date
- 2008
- Published By
- American Society for Testing and Materials (ASTM)
- Status
- Replace By
- ASTM E928-19
- Latest
- ASTM E928-19
- Scope
5.1 The melting temperature range of a compound broadens as the impurity level rises. This phenomenon is described approximately by the van’t Hoff equation for melting point depressions. Measuring and recording the instantaneous heat flow into the specimen as a function of temperature during such a melting process is a practical way for the generation of data suitable for analysis by the van’t Hoff equation.
5.2 The results obtained include: sample purity (expressed as mole percent); enthalpy of fusion (expressed as joules per mole); and the melting temperature (expressed in Kelvin) of the pure form of the major component.
5.3 Generally, the repeatability of this test method decreases as the purity level decreases. This test method is ordinarily considered unreliable when the purity level of the major component of the mixture is less than 98.5 mol8201;% or when the incremental enthalpy correction (c) exceeds 208201;% of the original detected enthalpy of fusion.
5.4 This test method is used for quality control, specification acceptance, and research.
1.1 This test method describes the determination of purity of materials greater than 98.5 mole percent purity using differential scanning calorimetry and the van’t Hoff equation.
1.2 This test method is applicable to thermally stable compounds with well-defined melting temperatures.
1.3 Determination of purity by this test method is only applicable when the impurity dissolves in the melt and is insoluble in the crystal.
1.4 There is no ISO method equivalent to this test method.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This 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 and health practices and determine the applicability of regulatory limitations prior to use.
ASTM E928-08(2014) Referenced Document
- ASTM E1970 Standard Practice for Statistical Treatment of Thermoanalytical Data
- ASTM E473 Standard Terminology Relating to Thermal Analysis
- ASTM E793 Standard Test Method for Enthalpies of Fusion and Crystallization by Differential Scanning Calorimetry
- ASTM E794 Standard Test Method for Melting and Crystallization Temperatures by Thermal Analysis
- ASTM E967 Standard Practice for Temperature Calibration of Differential Scanning Calorimeters and Differential Thermal Analyzers
- ASTM E968 Standard Practice for Heat Flow Calibration of Differential Scanning Calorimeters
ASTM E928-08(2014) history
- 2019 ASTM E928-19 Standard Test Method for Purity by Differential Scanning Calorimetry
- 2008 ASTM E928-08(2014) Standard Test Method for Purity by Differential Scanning Calorimetry
- 2008 ASTM E928-08 Standard Test Method for Determination of Purity by Differential Scanning Calorimetry
- 2003 ASTM E928-03 Standard Test Method for Determination of Purity by Differential Scanning Calorimetry
- 2001 ASTM E928-01 Standard Test Method for Determination of Purity by Differential Scanning Calorimetry
- 1996 ASTM E928-96 Standard Test Method for Determination of Purity by Differential Scanning Calorimetry
