ASTM E2253-03

Standard Method for Enthalpy Measurement Validation of Differential Scanning Calorimeters

SCOPE
1.1 This standard provides procedures for validating enthalpic measurements of differential scanning calorimeters (DSC) and analytical methods based upon the measurement of enthalpy or heat by DSC. Performance parameters determined include calorimetric repeatability (precision), detection limit, quantitation limit, linearity and bias. This method is applicable to both exothermic and endothermic events.
1.2 Validation of apparatus performance and analytical methods is requested or required for quality initiatives or where results may be used for legal purposes.
1.3 SI units are the standard.
1.4 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.

General Information

• Status: Historical
• Publication Date: 09-Jan-2003
• ICS: 17.200.10 - Heat. Calorimetry
• Technical Committee: E37 - Thermal Measurements
• Drafting Committee: E37.10 - Fundamental, Statistical and Mechanical Properties

Relations

• Referred By: ASTM E473-23a - Standard Terminology Relating to Thermal Analysis and Rheology
• Effective Date: 10-Jan-2003

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E2253–03
Standard Method for
Enthalpy Measurement Validation of Differential Scanning
Calorimeters
This standard is issued under the fixed designation E 2253; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 2.2 Other Standard:
United States Food and Drug Administration, Q2B Valida-
1.1 This standard provides procedures for validating enthal-
tion of Analytical Procedures: Methodology, 62 FR
pic measurements of differential scanning calorimeters (DSC)
27464, May 19, 1997
and analytical methods based upon the measurement of en-
thalpy or heat by DSC. Performance parameters determined
3. Terminology
include calorimetric repeatability (precision), detection limit,
3.1 Technical terms used in this standard are defined in
quantitation limit, linearity and bias. This method is applicable
Practice E 177 and in Terminologies E 473, E 1142, and
to both exothermic and endothermic events.
E 2161.
1.2 Validation of apparatus performance and analytical
methodsisrequestedorrequiredforqualityinitiativesorwhere
4. Summary of Test Method
results may be used for legal purposes.
4.1 Temperature and time are the primary independent
1.3 SI units are the standard.
parameters and heat flow is the primary dependent experimen-
1.4 This standard does not purport to address all of the
tal parameter provided by DSC. Integration of heat flow, as a
safety concerns, if any, associated with its use. It is the
function of time, yields enthalpy (heat).
responsibility of the user of this standard to establish appro-
4.1.1 Time, measured by the DSC apparatus, shall conform
priate safety and health practices and determine the applica-
to better than 0.1 % verified by Test Method E 1860 and
bility of regulatory limitations prior to use.
reported.
2. Referenced Documents 4.1.2 Heat flow, a measured value, is validated by its
integration over time to obtain the desired calorimetric (enthal-
2.1 ASTM Standards:
pic) information of interest. Determination and verification of
E 177 Practice for Use of the Terms Precision and Bias in
2 enthalpy is the primary scope of this test method.
ASTM Test Methods
2 4.2 Calorimetric validation of a differential scanning calo-
E 473 Terminology Relating to Thermal Analysis
rimetric apparatus at a single temperature is performed using
E 967 Practice for Temperature Calibration of Differential
the indium metal melt as an analyte.
Scanning Calorimeters and Differential Thermal Analyz-
2 4.3 Validation of a DSC method based upon enthalpic
ers
measurement may be performed using the test specimen as the
E 968 Practice for Heat Flow Calibration of Differential
2 analyte.
Scanning Calorimeters
4.4 The enthalpy of three (or more) specimens (nominally
E 1142 Terminology Relating to Thermophysical Proper-
2 representing the maximum, midpoint and minimum of the
ties
range of the test method) are measured in triplicate (or more).
E 1860 Test Method for Elapsed Time Calibration of Ther-
A fourth blank specimen, containing no analyte, is also
mal Analyzers
measured in triplicate.
E 1970 Practice for Statistical Treatment of Thermoanalyti-
cal Data
NOTE 1—Repeatability is determined by performing a sufficient num-
E 2161 Terminology Relating to Performance Validation in ber of determinations to calculate statistically valid estimates of the
standard deviation or relative standard deviation of the measurement.
Thermal Analysis
4.4.1 Calorimetric linearity and bias are determined from
the best-fit straight-line correlation of the results from mea-
This test method is under the jurisdiction ofASTM Committee E37 onThermal
surements of the three (or more) specimens.
Measurements and is the direct responsibility of Subcommittee E37.01 on Thermal
Analysis Methods.
Current edition approved Jan. 10, 2003. Published April 2003.
2 3
Annual Book of ASTM Standards, Vol 14.02. Available from FDA, 5600 Fishers Lane, Rockville, MD 20857.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E2253–03
4.4.2 Calorimetric detection limit and quantitation limit are 8. Calibration and Standardization
determined from the standard deviation of the blank determi-
8.1 After turning the power on, allow the instrument to
nation.
equilibrate for at least one hour prior to any measurements.
4.4.3 Calorimetric repeatability is determined from the re-
8.2 Perform any cleaning and calibration procedures de-
peatability measurement of the three (or more) specimens.
scribed by the manufacturer in the apparatus Operator’s
Manual.
5. Significance and Use
8.3 If not previously established, perform temperature and
5.1 This method may be used to determine and validate the
heat flow calibrations according to Practices E 967 and E 968
performance of a particular DSC apparatus.
respectively, using the same purge gas, purge gas flow rate and
5.2 This method may be used to determine and validate the
heating rate (here 10°C/min) to be used for validation experi-
performance of a particular method based upon a DSC enthal-
ments.
pic measurement.
8.4 If not previously established, obtain the instrument’s
5.3 This method may be used to determine the repeatability
elapsed time conformance using Test Method E 1860.
of a particular apparatus, operator or laboratory.
5.4 This method may be used for specification and regula- 9. Procedure for Determining Calorimetric Repeatability,
tory compliance purposes. Detection Limit, Quantitation Limit, Linearity, and
Bias
6. Apparatus
9.1 This process involves characterizing, in triplicate, a
6.1 Differential Scanning Calorimeter—The essential in-
blank and three (or more) test specimens taken to represent the
strumentation required to provide the minimum differential
low, medium and high extremes of the range over which
scanning calorimetric capability for this method include:
performance is to be validated.
6.1.1 DSC Test Chamber, composed of:
NOTE 4—The details of this procedure are written using indium as an
6.1.1.1 Furnace(s), to provide uniform controlled heating or
analyte. For validation of an enthalpic method, test specimens represent-
cooling of a specimen and reference to a constant temperature
ing the range of that method shall be used, and steps 9.2 to 9.7 replaced
or at a constant rate within the applicable temperature range of
with the enthalpic method procedure.
the test method.
9.2 Prepare three (or more) indium test specimens covering
6.1.1.2 Temperature Sensor, to provide an indication of the
the enthalpy or mass range of the tests. Nominal mass values
specimen temperature to readability required.
might be 1, 10, and 20 mg. Measure the mass of each of these
6.1.1.3 Differential Sensor, to detect a heat flow difference
specimens to the nearest 1 µg and record as M , M , and
min mid
between the specimen and reference.
M . Enclose each test specimen within clean specimen
max
6.1.1.4 A means of sustaining a test chamber environment
containers and lids. Also prepare a blank specimen that
of an inert purge gas at a rate of 10 to 50 mL/min 6 10 %.
contains no analyte but otherwise is similar to the specimens
NOTE 2—Typically, 99+ % pure nitrogen (or other inert gas, such as prepared above.
argon or helium) is employed when oxidation in air is a concern. Unless
NOTE 5—Most thermoanalytical methods cover 1.5 to 2 decades of
the effects of moisture are to be studied, the use of a dry purge gas is
range. The mass values selected should be approximately equally distrib-
recommended, especially for operation at subambient temperatures.
uted over the anticipated range. Other masses and mass ranges may be
6.1.2 Temperature Controller, capable of executing a spe-
used but shall be reported.
cific temperature program by operating the furnace(s) between
9.3 Load the largest specimen into the instrument chamber,
selected temperature limits at a rate of temperature change
purge the chamber with dry nitrogen (or other inert gas) at a
constant to 6 1 % or at an isothermal temperature constant to
flow rate of 10 to 50 mL/min 6 10 % throughout the
6 0.5°C.
experiment. An empty sample specimen container is loaded in
6.1.3 Recording Device, capable of recording and display-
the reference position.
ing the heat flow (DSC) curve as a function of time and
9.4 Erase any thermal history in the test specimen by
temperature.
heating the specimen to 180°C, then cool at 5°C/min to 120°C.
6.1.4 Containers, (pans, crucibles, vials, lids, closures,
The thermal curve need not be recorded.
seals, etc.) that are inert to the specimen and reference
9.5 Equilibrate at 120°C for one minute.
materials and that are of suitable structural shape and integrity
9.6 Heat the test specimen at 10°C/min through the indium
to contain the specimen and reference in accordance with the
melting transition to 180°C and record the thermal curve.
specific requirements of the test method.
NOTE 6—Other heating rates may be used but shall be reported.
6.2 Balance, of 100 mg or greater capacity to weigh
specimens and containers to 6 1 µg.
9.7 Coolthetestspecimento120°Cat5°C/min,thencoolto
ambient temperature at any convenient rate. The thermal curve
NOTE 3
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