ASTM_E_2603_-_15.pdf

Designation:E260315Standard Practice forCalibration of Fixed-Cell Differential Scanning Calorimeters1This standard is issued under the fixed designation E2603;the number immediately following the designation indicates the year oforiginal adoption or,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.1.Scope1.1 This practice covers the calibration of fixed-cell differ-ential scanning calorimeters over the temperature range from10 to+120C.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 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 prior to use.Specific precau-tionary statements are given in Section 7.2.Referenced Documents2.1 ASTM Standards:2E473 Terminology Relating to Thermal Analysis and Rhe-ologyE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE967 Test Method for Temperature Calibration of Differen-tial Scanning Calorimeters and Differential Thermal Ana-lyzersE968 Practice for Heat Flow Calibration of DifferentialScanning CalorimetersE1142 Terminology Relating to Thermophysical Properties3.Terminology3.1 Specific technical terms used in this practice are definedin Terminologies E473 and E1142,including differential scan-ning calorimeter,enthalpy,Kelvin,and transformation tem-perature.4.Summary of Practice4.1 This practice covers calibration of fixed-cell differentialscanning calorimeters.These calorimeters differ from anothercategory of differential scanning calorimeter in that the formerhave generally larger sample volumes,slower maximum tem-perature scan rate capabilities,provision for electrical calibra-tion of heat flow,and a smaller range of temperature overwhich they operate.The larger sample cells,and their lack ofdisposability,make inapplicable the calibration methods ofPractices E967 and E968.4.2This practice consists of heating the calibration mate-rials in aqueous solution at a controlled rate through a region ofknown thermal transition.The difference in heat flow betweenthe calibration material and a reference material,both relativeto a heat reservoir,is monitored and continuously recorded.Atransition is marked by the absorption or release of energy bythe specimen resulting in a corresponding peak in the resultingcurve.4.3 The fixed-cell calorimeters typically,if not always,haveelectrical heating facilities for calibration of the heat-flow axis.Despite the use of resistance heating for calibration,a chemicalcalibration serves to verify the correct operation of the calibra-tion mechanism and the calorimeter.The thermal denaturationof chicken egg white lysozyme is used in this practice forverification of the proper functioning of the instrumentssystems.The accuracy with which the denaturation enthalpy ofchicken egg white lysozyme is currently known,65%,is suchthat it should be rare that a calorimeter provides a value outsidethat established in the literature for this reference material.5.Significance and Use5.1 Fixed-cell differential scanning calorimeters are used todetermine the transition temperatures and energetics of mate-rials in solution.For this information to be accepted withconfidence in an absolute sense,temperature and heat calibra-tion of the apparatus or comparison of the resulting data to thatof known standard materials is required.5.2 This practice is useful in calibrating the temperature andheat flow axes of fixed-cell differential scanning calorimeters.6.Apparatus6.1 Apparatus shall be:1This practice is under the jurisdiction of ASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.09 on Micro-calorimetry.Current edition approved May 1,2015.Published August 2015.Originallyapproved in 2008.Last previous edition approved in 2008 as E2603 08.DOI:10.1520/E2603-15.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.1.1 Differential Scanning Calorimeter(DSC),capable ofheating a test specimen and a reference material at a controlledrate and of automatically recording the differential heat flowbetween the sample and the reference material to the requiredsensitivity and precision.6.1.2 DSC Test Chamber,composed of:6.1.2.1 Adevice(s)to provide uniform controlled heating orcooling of a specimen and reference to a constant temperatureor at a constant rate within the applica