1、Designation:E2253081Designation: E2253 11Standard Test Method forTemperature and Enthalpy Measurement Validation ofDifferential Scanning Calorimeters1This standard is issued under the fixed designation E2253; the number immediately following the designation indicates the year oforiginal adoption or,
2、 in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTESections 3.1 and 6.1.3 were corrected editorially in August 2009.1. Scope1.1 This test
3、method provides procedures for validating enthalpic temperature and enthalpy measurements of differentialscanning calorimeters (DSC) and analytical methods based upon the measurement of temperature or enthalpy (or heat), orheatboth, by DSC. Performance parameters determined include temperature and c
4、alorimetric repeatability (precision), detectionlimit, quantitation limit, linearity, and bias. This test 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 resultsmay
5、 be used for legal purposes.1.3 The values stated in SI units are to regarded as standard. No other units of measurement are included in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of thi
6、s standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE473 Terminology Relating to Thermal Analysis and
7、 RheologyE967 Test Method for Temperature Calibration of Differential Scanning Calorimeters and Differential Thermal AnalyzersE968 Practice for Heat Flow Calibration of Differential Scanning CalorimetersE1142 Terminology Relating to Thermophysical PropertiesE1860 Test Method for Elapsed Time Calibra
8、tion of Thermal AnalyzersE1970 Practice for Statistical Treatment of Thermoanalytical DataE2161 Terminology Relating to Performance Validation in Thermal Analysis2.2 Other Standard:United States Food and Drug Administration,Q2B Validation of Analytical Procedures: Methodology, 62 FR 27464, May 19,19
9、97 FDA Publications:3Q2B Validation of Analytical Procedures Methodology, 62 FR 27464, May 19, 19973. Terminology3.1Technical3.1 Technical terms used in this standard are defined in Practice E177 and in Terminologies E473, E1142, andE2161 including analyte, detection limit, differential scanning cal
10、orimetry, enthalpy, extrapolated onset value (temperature),linearity, mean, precision, quantitation limit, relative standard deviation, repeatability, standard deviation, thermal curve, andvalidation.1This test method is under the jurisdiction of ASTM Committee E37 on Thermal Measurements and is the
11、 direct responsibility of Subcommittee E37.10 on Fundamental,Statistical and Mechanical Properties.Current edition approved Sept. 1, 2008. Published November 2008. Originally approved in 2003. Last previous edition approved in 2003 as E225303. DOI:10.1520/E2253-08E01.Current edition approved Dec. 1,
12、 2011. Published February 2012. Originally approved in 2003. Last previous edition approved in 2008 as E2253 081. DOI:10.1520/E2253-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume in
13、formation, refer to the standards Document Summary page on the ASTM website.3Available from Food and Drug Administration (FDA), 5600 Fishers Ln., Rockville, MD 20857, http:/www.fda.gov.3Available from Food and Drug Administration (FDA), 10903 New Hampshire Ave., Silver Spring, MD 20993-0002, http:/w
14、ww.fda.gov.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consu
15、lt prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Summary of Test Method4.1 Tempera
16、ture and time are the primary independent parameters and heat flow is the primary dependent experimentalparameter provided by DSC. Integration of heat flow, as a function of time, yields enthalpy (heat).4.1.1 Time, measured by the DSC apparatus, shall conform to better than 0.1 % verified by Test Me
17、thod E1860 and reported.4.1.2Heat flow, a measured value, is validated by its integration over time to obtain the desired calorimetric (enthalpic)information of interest. Determination and verification of enthalpy is the primary scope of this test method.4.1.2 Temperature is directly measured by a t
18、emperature sensor that is an integral part of the differential scanning calorimetryapparatus.4.1.3 Heat flow, a measured value, is validated by its integration over time to obtain the desired calorimetric (enthalpic)information of interest.4.2 Calorimetric validation of a differential scanning calor
19、imetric apparatus at a single temperature is performed using theindium metal melt as an analyte.4.3 Validation of a DSC method based upon enthalpic measurement may be performed using the test specimen as the analyte.4.4 The enthalpy of three (or more) specimens (nominally representing the maximum, m
20、idpoint and minimum of the range ofthe test method) are measured in triplicate (or more).Afourth blank specimen, containing no analyte, is also measured in triplicate.NOTE 1Repeatability is determined by performing a sufficient number of determinations to calculate statistically valid estimates of t
21、he standarddeviation or relative standard deviation of the measurement.4.4.1 Calorimetric linearity and bias are determined from the best-fit straight-line correlation of the results from measurementsof the three (or more) specimens.4.4.2 Calorimetric detection limit and quantitation limit are deter
22、mined from the standard deviation of the blank determination.4.4.3 Calorimetric repeatability is determined from the repeatability measurement of the three (or more) specimens.4.5 The temperature validation of a differential scanning calorimetric apparatus is performed at three temperatures using in
23、dium,bismuth, and zinc metal melts as an analyte (see Section 7).4.5.1 The melting temperature of three (or more) materials representing the maximum, midpoint, and minimum of thetemperature range of the test method are measured in triplicate (or more) (see Note 1).4.5.2 Temperature linearity and bia
24、s are determined from the best-fit straight-line correlation of the results from the temperaturemeasurements at the three (or more) temperatures.4.5.3 Temperature repeatability, detection limit and quantitation limit are determined from the standard deviation of the replicatetemperature measurements
25、.5. Significance and Use5.1 This test method may be used to determine and validate the performance of a particular DSC apparatus.5.2 This test method may be used to determine and validate the performance of a particular method based upon a DSCtemperature and enthalpic measurement, or both.5.3 This t
26、est method may be used to determine the repeatability of a particular apparatus, operator, or laboratory.5.4 This test method may be used for specification and regulatory compliance purposes.6. Apparatus6.1 Differential Scanning Calorimeter (DSC)The essential instrumentation required to provide the
27、minimum differentialscanning calorimetric capability for this test method includes:6.1.1 DSC Test Chamber, composed of: DSC Test Chamber, composed of:6.1.1.1 Furnace(s), , to provide uniform controlled heating or cooling of a specimen and reference to a constant temperatureor at a constant rate with
28、in the applicable temperature range of the test method.6.1.1.2 Temperature Sensor, , to provide an indication of the specimen temperature to readability required.6.1.1.3 Differential Sensor, , to detect a heat flow difference between the specimen and reference.6.1.1.4 A means of sustaining a test ch
29、amber environment of an inert purge gas at a rate of 10 to 50 mL/min 6 10 %.NOTE 2Typically, 99+ % pure nitrogen (or other inert gas, such as argon or helium) is employed when oxidation in air is a concern. Unless the effectsof moisture are to be studied, the use of a dry purge gas is recommended, e
30、specially for operation at subambient temperatures.6.1.2 Temperature Controller, capable of executing a specific temperature program by operating the furnace(s) between selectedtemperature limits at a rate of temperature change constant to 6 1 % or at an isothermal temperature constant to 6 0.5C.6.1
31、.3 Data Collection Device, to provide a means of acquiring, storing, and displaying measured or calculated signals, or both.The minimum output signals required for differential scanning calorimetry are heat flow, temperature, and time.6.1.4 Containers, (pans, crucibles, vials, lids, closures, seals,
32、 etc.) that are inert to the specimen and reference materials and thatare of suitable structural shape and integrity to contain the specimen and reference in accordance with the specific requirementsof the test method.6.2 Balance, of 100 mg or greater capacity to weigh specimens and containers to 6
33、1 g.NOTE 3A balance of this high precision is required so that weighing imprecision is not part of the overall method imprecision.E2253 1127. Reagents and Materials7.1 Indium Metal, 99.99+% purity, preferably a certified reference material for which the melting temperature and enthalpy offusion are
34、known. Indium (In) Metal, 99.99+ % purity, preferably a certified reference material for which the melting temperatureand enthalpy of fusion are known.7.2 Bismuth (Bi) Metal, 99.99+ % purity, preferably a certified reference material for which the melting temperature is known.7.3 Zinc (Zn) Metal, 99
35、.99+ % purity, preferably a certified reference material for which the melting temperature is known.8. Calibration and Standardization8.1 After turning the power on, allow the instrument to equilibrate for at least one hour prior to any measurements.8.2 Perform any cleaning and calibration procedure
36、s described by the manufacturer in the apparatus Operators Manual.8.3 If not previously established, perform temperature and heat flow calibrations according to Practices E967 and E968respectively, using the same purge gas, purge gas flow rate and heating rate (here 10 C/min) to be used for validati
37、on experiments.8.4 If not previously established, obtain the instruments elapsed time conformance using Test Method E1860.9. Procedure for Determining Calorimetric Repeatability, Detection Limit, Quantitation Limit, Linearity, and Bias9.1 This process involves characterizing, in triplicate, a blank
38、and three (or more) test specimens taken to represent the low,medium and high extremes of the range over which performance is to be validated.NOTE 4The details of this procedure are written using indium as an analyte. For validation of an enthalpic method, test specimens representing therange of tha
39、t method shall be used, and steps 9.2 to 9.7 replaced with the enthalpic method procedure.9.2 Prepare three (or more) indium test specimens covering the enthalpy or mass range of the tests. Nominal mass values mightbe 1, 10, and 20 mg. Measure the mass of each of these specimens to the nearest 1 g a
40、nd record as Mmin, Mmid, and Mmax. Encloseeach test specimen within clean specimen containers and lids.Also prepare a blank specimen that contains no analyte but otherwiseis similar to the specimens prepared above.NOTE 5Most thermoanalytical methods cover 1.5 to 2 decades of range. The mass values s
41、elected should be approximately equally distributed overthe anticipated range. Other masses and mass ranges may be used but shall be reported.9.3 Load the largest specimen into the instrument chamber, purge the chamber with dry nitrogen (or other inert gas) at a flowrate of 10 to 50 mL/min 6 10 % th
42、roughout the experiment. An empty sample specimen container is loaded in the referenceposition.9.4 Erase any thermal history in the test specimen by heating the specimen to 180 C, then cool at 5 C/min to 120 C. Thethermal curve need not be recorded.9.5 Equilibrate at 120 C for one minute.9.6 Heat th
43、e test specimen at 10 C/min through the indium melting transition to 180 C and record the thermal curve.NOTE 6Other heating rates may be used but shall be reported.9.7 Cool the test specimen to 120 C at 5C/min, then cool to ambient temperature at any convenient rate. The thermal curveneed not be rec
44、orded.9.8 Construct a baseline for the melting endotherm by selecting a point on the curve immediately before and anotherimmediately after the endotherm. Record the temperatures of these two points as T1and T2. Construct a linear baseline betweenthe two points (see Fig. 1).9.9 Integrate, as a functi
45、on of time, the heat flow described by the constructed baseline and the melting endotherm. Record thisvalue as enthalpy (DQmax(1), in mJ).9.10 Repeat steps 9.3 through 9.9 for the medium mass test specimen from step 9.2. Use the same integration limits (T1andT2) determined in step 9.8. Record this v
46、alue as enthalpy (DQmid(1) , in mJ).NOTE 7Loading and unloading of the specimen is required to determine analytical repeatability. If only instrumental repeatability is beingdetermined, the specimen may be left in place between determinations.9.11 Repeat steps 9.3 through 9.9 for the small mass test
47、 specimen from step 9.2. Use the same integration limits (T1and T2)determined in step 9.8. Record this value as enthalpy (DQmin(1), in mJ).9.12 Repeat steps 9.3 through 9.9 for the blank test specimen from step 9.2. Use the same integration limits (T1and T2)determined in step 9.8 (see Fig. 2). Recor
48、d this value as enthalpy (DQo(1), in mJ).NOTE 8Observe and record the sign of the value for D Qo. It may be positive or negative.9.13 Repeat steps 9.5 through 9.9 two more times for the large mass specimen. Remove the specimen from the DSC samplechamber and reload it between each determination. Reco
49、rd these values as enthalpy (DQmax(2) and DQmax(3), in mJ).9.14 Repeat steps 9.5 through 9.9 two more times for the medium mass specimen. Remove the specimen from the DSC samplechamber and reload it between each determination. Record these values as enthalpy (DQmid(2) and DQmid(3), in mJ).9.15 Repeat steps 9.5 through 9.9 two more times for the low mass specimen. Remove the specimen from the DSC samplechamber and reload it between each determination. Record these values as enthalpy (DQmin(2) and DQmin(3), in mJ).E2253 1139.16 Repeat steps 9.5 through
