1、Designation: E2253 16Standard 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, in the case of revi
2、sion, 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.1. Scope*1.1 This test method provides procedures for validatingtemperature and enthalpy measurements of differe
3、ntial scan-ning calorimeters (DSC) and analytical methods based uponthe measurement of temperature or enthalpy (or heat), or both,by DSC. Performance parameters determined include tempera-ture and calorimetric repeatability (precision), detection limit,quantitation limit, linearity, and bias. This t
4、est method isapplicable to exothermic events.1.2 Validation of apparatus performance and analyticalmethods is requested or required for quality initiatives or whereresults may be used for legal purposes.1.3 The values stated in SI units are to regarded as standard.No other units of measurement are i
5、ncluded in this standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations pri
6、or to use.2. Referenced Documents2.1 ASTM Standards:2E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE473 Terminology Relating to Thermal Analysis and Rhe-ologyE967 Test Method for Temperature Calibration of Differen-tial Scanning Calorimeters and Differential Thermal Ana-ly
7、zersE968 Practice for Heat Flow Calibration of DifferentialScanning CalorimetersE1142 Terminology Relating to Thermophysical PropertiesE1860 Test Method for Elapsed Time Calibration of Ther-mal AnalyzersE1970 Practice for Statistical Treatment of ThermoanalyticalDataE2161 Terminology Relating to Per
8、formance Validation inThermal Analysis and Rheology2.2 FDA Publications:3Q2B Validation of Analytical Procedures Methodology, 62FR 27464, May 19, 19973. Terminology3.1 Technical terms used in this standard are defined inPractice E177 and in Terminologies E473, E1142, and E2161including analyte, dete
9、ction limit, differential scanningcalorimetry, enthalpy, extrapolated onset value (temperature),linearity, mean, precision, quantitation limit, relative standarddeviation, repeatability, standard deviation, thermal curve, andvalidation.4. Summary of Test Method4.1 Temperature and time are the primar
10、y independentparameters and heat flow is the primary dependent experimen-tal parameter provided by DSC. Integration of heat flow, as afunction of time, yields enthalpy (heat).4.1.1 Time, measured by the DSC apparatus, shall conformto better than 0.1 % verified by Test Method E1860 andreported.4.1.2
11、Temperature is directly measured by a temperaturesensor that is an integral part of the differential scanningcalorimetry apparatus.4.1.3 Heat flow, a measured value, is validated by itsintegration over time to obtain the desired calorimetric (en-thalpic) information of interest.4.2 Calorimetric vali
12、dation of a differential scanning calo-rimetric apparatus at a single temperature is performed usingthe indium metal melt as an analyte.4.3 Validation of a DSC method based upon enthalpicmeasurement may be performed using the test specimen as theanalyte.1This test method is under the jurisdiction of
13、ASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.10 onFundamental, Statistical and Mechanical Properties.Current edition approved April 1, 2016. Published April 2016. Originallyapproved in 2003. Last previous edition approved in 2011 as E2253 11. DOI:10.
14、1520/E2253-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Food and Drug Administration (F
15、DA), 10903 New HampshireAve., Silver Spring, MD 20993-0002, http:/www.fda.gov.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.4 The enthalpy of three (or more) specime
16、ns (nominallyrepresenting the maximum, midpoint and minimum of therange of the test method) are measured in triplicate (or more).A fourth blank specimen, containing no analyte, is alsomeasured in triplicate.NOTE 1Repeatability is determined by performing a sufficient numberof determinations to calcu
17、late statistically valid estimates of the standarddeviation or relative standard deviation of the measurement.4.4.1 Calorimetric linearity and bias are determined fromthe best-fit (linear regression) straight-line correlation of theresults from measurements of the three (or more) specimens.4.4.2 Cal
18、orimetric detection limit and quantitation limit aredetermined from the standard deviation of the blank determi-nation.4.4.3 Calorimetric repeatability is determined from the re-peatability measurement of the three (or more) specimens.4.5 The temperature validation of a differential scanningcalorime
19、tric apparatus is performed at three temperatures usingindium, bismuth, and zinc metal melts as an analyte (seeSection 7).4.5.1 The melting temperature of three (or more) materialsrepresenting the maximum, midpoint, and minimum of thetemperature range of the test method are measured in triplicate(or
20、 more) (see Note 1).4.5.2 Temperature linearity and bias are determined fromthe best-fit (linear regression) straight-line correlation of theresults from the temperature measurements at the three (ormore) temperatures.4.5.3 Temperature repeatability, detection limit and quanti-tation limit are deter
21、mined from the standard deviation of thereplicate temperature measurements.5. Significance and Use5.1 This test method may be used to determine and validatethe performance of a particular DSC apparatus.5.2 This test method may be used to determine and validatethe performance of a particular method b
22、ased upon a DSCtemperature and enthalpic measurement, or both.5.3 This test method may be used to determine the repeat-ability of a particular apparatus, operator, or laboratory.5.4 This test method may be used for specification andregulatory compliance purposes.6. Apparatus6.1 Differential Scanning
23、 Calorimeter (DSC)The essentialinstrumentation required to provide the minimum differentialscanning calorimetric capability for this test method includes:6.1.1 DSC Test Chamber, composed of:6.1.1.1 Furnace(s), to provide uniform controlled heating orcooling of a specimen and reference to a constant
24、temperatureor at a constant rate within the applicable temperature range ofthe test method.6.1.1.2 Temperature Sensor, to provide an indication of thespecimen temperature to readability required.6.1.1.3 Differential Sensor, to detect a heat flow differencebetween the specimen and reference.6.1.1.4 A
25、 means of sustaining a test chamber environmentof 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 asargon or helium) is employed when oxidation in air is a concern. Unlessthe effects of moisture are to be studied, the use of a dry
26、 purge gas isrecommended, especially for operation at subambient temperatures.6.1.2 Temperature Controller, capable of executing a spe-cific temperature program by operating the furnace(s) betweenselected temperature limits at a rate of temperature changeconstant to 61 % or at an isothermal temperat
27、ure constant to60.5C.6.1.3 Data Collection Device, to provide a means ofacquiring, storing, and displaying measured or calculatedsignals, or both. The minimum output signals required fordifferential scanning calorimetry are heat flow, temperature,and time.6.1.4 Containers, (pans, crucibles, vials, l
28、ids, closures,seals, etc.) that are inert to the specimen and referencematerials and that are of suitable structural shape and integrityto contain the specimen and reference in accordance with thespecific requirements of the test method.6.2 Balance, of 100 mg or greater capacity to weighspecimens an
29、d containers to 61 g.NOTE 3A balance of this high precision is required so that weighingimprecision is not part of the overall method imprecision.7. Reagents and Materials7.1 Indium (In) Metal, 99.99+ % purity, preferably a certi-fied reference material for which the melting temperature andenthalpy
30、of fusion are known.7.2 Bismuth (Bi) Metal, 99.99+ % purity, preferably a cer-tified reference material for which the melting temperature isknown.7.3 Zinc (Zn) Metal, 99.99+ % purity, preferably a certifiedreference material for which the melting temperature is known.8. Calibration and Standardizati
31、on8.1 After turning the power on, allow the instrument toequilibrate for at least one hour prior to any measurements.8.2 Perform any cleaning and calibration procedures de-scribed by the manufacturer in the apparatus OperatorsManual.8.3 If not previously established, perform temperature andheat flow
32、 calibrations according to Test Method E967 andPractice E968 respectively, using the same purge gas, purgegas flow rate and heating rate (here 10C/min) to be used forvalidation experiments.8.4 If not previously established, obtain the instrumentselapsed time conformance using Test Method E1860.9. Pr
33、ocedure for Determining Calorimetric Repeatability,Detection Limit, Quantitation Limit, Linearity, and Bias9.1 This process involves characterizing, in triplicate, ablank and three (or more) test specimens taken to represent thelow, medium and high extremes of the range over whichperformance is to b
34、e validated.E2253 162NOTE 4The details of this procedure are written using indium as ananalyte. For validation of an enthalpic method, test specimens represent-ing the range of that method shall be used, and steps 9.2 to 9.7 replacedwith the enthalpic method procedure.9.2 Prepare three (or more) ind
35、ium test specimens coveringthe enthalpy or mass range of the tests. Nominal mass valuesmight be 1, 10, and 20 mg. Measure the mass of each of thesespecimens to the nearest 1 g and record as Mmin, Mmid, andMmax. Enclose each test specimen within clean specimencontainers and lids. Also prepare a blank
36、 specimen thatcontains no analyte but otherwise is similar to the specimensprepared above.NOTE 5Most thermoanalytical methods cover 1.5 to 2 decades ofrange. The mass values selected should be approximately equally distrib-uted over the anticipated range. Other masses and mass ranges may beused but
37、shall be reported.9.3 Load the largest specimen into the instrument chamber,purge the chamber with dry nitrogen (or other inert gas) at aflow rate of 10 to 50 mL/min 6 10 % throughout theexperiment. An empty sample specimen container is loaded inthe reference position.9.4 Erase any thermal history i
38、n the test specimen byheating the specimen to 180C, then cool at 5C/min to 120C.The thermal curve need not be recorded.9.5 Equilibrate at 120C for one minute.9.6 Heat the test specimen at 10C/min through the indiummelting transition to 180C and record the thermal curve.NOTE 6Other heating rates may
39、be used but shall be reported.9.7 Cool the test specimen to 120C at 5C/min, then cool toambient temperature at any convenient rate. The thermal curveneed not be recorded.9.8 Construct a baseline for the melting endotherm byselecting a point on the curve immediately before and anotherimmediately afte
40、r the endotherm. Record the temperatures ofthese two points as T1and T2. Construct a linear baselinebetween the two points (see Fig. 1).9.9 Integrate, as a function of time, the heat flow describedby the constructed baseline and the melting endotherm. Recordthis value as enthalpy (Qmax(1), in mJ).9.
41、10 Repeat steps 9.3 through 9.9 for the medium mass testspecimen from step 9.2. Use the same integration limits (T1andT2) determined in step 9.8. Record this value as enthalpy(Qmid(1) , in mJ).NOTE 7Loading and unloading of the specimen is required todetermine analytical repeatability. If only instr
42、umental repeatability isbeing determined, the specimen may be left in place between determina-tions.9.11 Repeat steps 9.3 through 9.9 for the small mass testspecimen from step 9.2. Use the same integration limits (T1andT2) determined in step 9.8. Record this value as enthalpy(Qmin(1), in mJ).9.12 Re
43、peat steps 9.3 through 9.9 for the blank test speci-men from step 9.2. Use the same integration limits (T1and T2)determined in step 9.8 (see Fig. 2). Record this value asenthalpy (Qo(1), in mJ).NOTE 8Observe and record the sign of the value for Qo. It may bepositive or negative.9.13 Repeat steps 9.5
44、 through 9.9 two more times for thelarge mass specimen. Remove the specimen from the DSCsample chamber and reload it between each determination.Record these values as enthalpy (Qmax(2) and Qmax(3), inmJ).9.14 Repeat steps 9.5 through 9.9 two more times for themedium mass specimen. Remove the specime
45、n from the DSCsample chamber and reload it between each determination.Record these values as enthalpy (Qmid(2) and Qmid(3), inmJ).FIG. 1 Integration of Large Indium Melting EndothermE2253 1639.15 Repeat steps 9.5 through 9.9 two more times for thelow mass specimen. Remove the specimen from the DSCsa
46、mple chamber and reload it between each determination.Record these values as enthalpy (Qmin(2) and Qmin(3), inmJ).9.16 Repeat steps 9.5 through 9.9 two more times for theblank specimen. Remove the specimen from the DSC samplechamber and reload it between each determination. Recordthese values as ent
47、halpy (Qo(2) and Qo(3), in mJ).9.17 Calculate the mean (Q), standard deviation (s) andrelative standard deviation (RSD) for the enthalpy from thereplicate determinations made on each of the three massspecimens (see Practice E1970). Record these values as Qmax,Qmid, Qmin, smax, smid, smin, and RSDmax
48、, RSDmid, and RSDmin,respectively. Calculate the mean and standard deviation for theenthalpy determination of the blank. Record these values as Qoand sorespectively.9.18 Using the standard deviation for the enthalpy of theblank (so) from step 9.17, determine the instrument detectionlimit (DL) and qu
49、antitation limit (QL) as in calculations 11.2and 11.3. Report DL and QL.9.19 Calculate the pooled relative standard deviation for theenthalpy of fusion from the RSDmax, RSDmid, and RSDmin,obtained in step 9.17 (see Practice E1970). Report this value asthe Calorimetric Repeatability value (r).9.20 Using the three (or more) mass values from step 9.2 asthe independent (X) values and the three (or more) meanenthalpy values from step 9.17 as the dependent (Y) values,determine the least square (linear regression) best fit values forthe slope (m)inmJ
