1、Designation: E1868 10Standard Test Method forLoss-On-Drying by Thermogravimetry1This standard is issued under the fixed designation E1868; 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 paren
2、theses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method describes a procedure for determiningthe amount of volatile matter of any kind that is driven off froma test specimen under a specifi
3、c set of temperature and timeconditions. This test method determines only the mass ofmaterial lost, not its identity.1.2 This test method is applicable to a wide variety of solidor liquid materials, mixtures, or blends where the majorcomponent is stable at the test temperature.NOTE 1This test method
4、 can be applied to the analysis of volatileorganic compounds (VOC) content in metalworking fluids and directcontact lubricants subject to South CoastAir Quality Management District(SCAQMD) Rule 1144.1.3 The applicable temperature range for this test method isgenerally between ambient temperature and
5、 1000C.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 There is no ISO method equivalent to this test standard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It
6、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.2. Referenced Documents2.1 ASTM Standards:2D6 Test Method for Loss on Heating of Oil and AsphalticCompoundsD1475 Test Method
7、 For Density of Liquid Coatings, Inks,and Related ProductsD1509 Test Methods for Carbon BlackHeating LossD2216 Test Methods for Laboratory Determination of Wa-ter (Moisture) Content of Soil and Rock by MassD2288 Test Method for Weight Loss of Plasticizers onHeating3D2595 Test Method for Evaporation
8、Loss of LubricatingGreases Over Wide-Temperature RangeD2832 Guide for Determining Volatile and NonvolatileContent of Paint and Related CoatingsD3175 Test Method for Volatile Matter in the AnalysisSample of Coal and CokeD4017 Test Method for Water in Paints and Paint Materialsby Karl Fischer MethodD4
9、893 Test Method for Determination of Pitch VolatilityE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE359 Test Methods for Analysis of Soda Ash (SodiumCarbonate)E473 Terminology Relating to Thermal Analysis and Rhe-ologyE691 Practice for Conducting an Interlaboratory Study t
10、oDetermine the Precision of a Test MethodE897 Test Method for Volatile Matter in the AnalysisSample of Refuse-Derived FuelE1142 Terminology Relating to Thermophysical PropertiesE1582 Practice for Calibration of Temperature Scale forThermogravimetryE1860 Test Method for Elapsed Time Calibration of Th
11、er-mal AnalyzersE2040 Test Method for Mass Scale Calibration of Thermo-gravimetric Analyzers2.2 SCAQMD Documents:4Rule 1144 Metalworking Fluids and Direct-Contact Lubri-cants3. Terminology3.1 Definitions:3.1.1 Specific technical terms used in this test method aredefined in Terminology E473 and Termi
12、nology E1142, includethermogravimetry, thermogravimetric analyzer, repeatability,and reproducibility.1This test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.01 on Calo-rimetry and Mass Loss.Current edition approved
13、July 1, 2010. Published August 2010. Originallyapproved in 1997. Last previous edition approved in 2009 as E1868 09. DOI:10.1520/E1868-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer service at serviceastm.org. For Annual Book of ASTMStandards volume
14、information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4Available from South Coast Air Quality Management District (SCAQMD),21865 Copley Drive, Diamond Bar, CA, 91765, http:/aqmd.gov.
15、1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Summary of Test Method4.1 A specimen of known mass is heated at a constanttemperature while its mass is continuously measured as afunction of time. At the end of a pre-determined tim
16、e interval,or when the loss reaches a pre-determined rate, the mass loss ofthe specimen is recorded as a percent of the original mass. Thisvalue is identified as the loss-on-drying (LOD) value. TheLOD value is a function of both temperature and time.Therefore these values must be identified and repo
17、rted. Atypical LOD value is reported as LOD = XX % (60 min at120C). The volatile content, V (g/L), or VOC content, VOC(g/L), may be calculated.NOTE 2For SCAQMD Rule 1144 purposes, at the end of a pre-determined time interval and specified temperature, the mass loss of thespecimen is recorded as a pe
18、rcent of the original mass. Additionally, thedensity and water content of the sample are determined. These values arethen used to calculate the VOC content.5. Significance and Use5.1 This test method is used to estimate the amount ofvolatile materials present in a material.5.2 This test method is us
19、eful for design purposes, serviceevaluation, regulatory statutes, manufacturing control, qualitycontrol, specification acceptance, development, and research.5.3 The results obtained by this test method may be equiva-lent to those obtained by other test methods and may be knownby other terms in their
20、 respective fields. Other tests and termsencountered include loss-on-heating (see Footnote5and TestMethods D6, D2288, and E359); heating loss (see Test MethodD1509); evaporative loss (see Test Method D2595); volatileorganic carbon, moisture, or water (see Test Methods D2216and D3175); volatility (se
21、e Test Method D4893); highlyvolatile matter (see Test Method E897); and volatile content(see Guide D2832).6. Interferences6.1 Because the specimen size is usually small, care must betaken to ensure that each specimen is representative of thesample as a whole.6.2 This test procedure measures total ma
22、ss loss underspecific experimental conditions. If more than one volatilecomponent is present, the results will reflect the total of allthose volatile components present.6.3 If the test temperature is set too high, the resultantweight loss may include some decomposition of the matrixmaterial.6.4 When
23、 calculating VOC content for SCAQMDRule 1144 purposes, it may be necessary to measure andcorrect for water content. Refer to Test Method D4017 todetermine the water content of the specimen.7. Apparatus7.1 Thermogravimetric Analyzer, capable of continuouslyrecording specimen mass and temperature as a
24、 function of timeconsisting of:7.1.1 Electrobalance, with a minimum specimen capacityof 100 mg capable of continuously recording 10 g or smallermass changes. Performance may be verified in accordance withTest Method E2040.7.1.2 Specimen Holders, that are inert to the specimen andof suitable structur
25、al shape and integrity to contain the 10 mgtest specimen used in this test method. Specimen holders,composed of platinum, aluminum, or quartz may be used, butother holders may be considered.NOTE 3For SCAQMD Rule 1144 purposes, specimen holders mustbe shallow and composed of platinum.7.1.3 Furnace, w
26、hose temperature can be controlled from25 to 1000C, capable of a heating rate, at a minimum, of5C/min and of maintaining a set temperature isothermallywithin that range to 62C.7.1.4 Temperature Sensor to provide an indication of thespecimen or furnace temperature, or both, to 60.1C.NOTE 4The tempera
27、ture sensor shall be placed as close as practical tothe test specimen without disturbing weight measurements or as specifiedby the manufacturer. In addition, it must be located in exactly the sameposition during analytical determinations as used during calibration.7.1.5 Specimen Atmosphere Control S
28、ystem, capable ofsupplying inert dry gas (usually purified grade nitrogen) withan operator selectable flow rate of 50 to 100 mL/min to within65 mL/min.NOTE 5For SCAQMD Rule 1144 purposes, use purified grade nitro-gen for both the sample purge flow and balance protection flow.7.1.6 Measurement System
29、, to continuously record speci-men temperature to within 60.1C over the range from 25 to1000C.7.1.7 Timer, capable of continuously recording elapsed timeup to 20 h to within 6 0.1 min or 61 %, whichever is greater.Performance may be verified in accordance with Test MethodE1860.7.1.8 Controller, capa
30、ble of executing a temperature pro-gram by operating the furnace from 25 to 1000C at aminimum rate of 5C/min to within 60.1C/min and ofmaintaining a set temperature isothermally within the range of62C.7.1.9 Data Collection Device, provide a means of acquir-ing, storing, and displaying measured or ca
31、lculated signals, orboth. The minimum output signals required for thermogravi-metric analysis (TGA) are mass, temperature, and time.7.1.10 While not required, it is convenient to have a dataanalysis device that will continuously perform and display thefollowing calculation:7.1.10.1 Specimen mass as
32、a percent of the initial mass.7.1.10.2 Specimen mass rate of change (in mass %/min)capable of detecting 0.01 %/min.7.1.11 While not required, it is convenient to have anexperiment control device capable of terminating the experi-ment under the following conditions:7.1.11.1 When an operator selected
33、period of time at anisothermal temperature condition has elapsed, and7.1.11.2 When an operator selected rate of mass loss isachieved.5Formulary Vol XVII is available from U.S. Pharmacopeia (USP), 12601Twinbrook Pkwy., Rockville, MD 20852-1790, http:/www.usp.org.E1868 1027.2 Gas Exhaust System capabl
34、e of removing from thelaboratory the potentially noxious purge gas effluent of thesystem above.7.3 Inert GasPurified grade nitrogen.7.4 Micropipettes or Syringes, for liquids, capable of dis-pensing up to 15 6 1 L.8. Hazards8.1 Toxic or corrosive effluent, or both, may be releasedwhen heating some m
35、aterials and could be harmful to person-nel and to apparatus.9. Sampling9.1 Samples are usually analyzed on “as received” basis.Should some thermal or mechanical treatment (such as grind-ing or sieving) be applied to the sample prior to analysis, itshall be indicated in the report. Grinding may rele
36、ase volatilesdue to the heating generated by grinding process.9.2 Since small test specimens are used, they must behomogeneous and representative of the sample. The mixing orstirring of samples prior to analysis is recommended wheneverpossible.9.3 If experiments are to be initiated at room temperatu
37、re,equilibrate samples in their sealed containers to room tempera-ture prior to testing.NOTE 6For SCAQMD Rule 1144 purposes, samples containing solidparticles should be filtered prior to analysis.10. Calibration10.1 Calibrate the temperature signal from the apparatusaccording to Practice E1582 using
38、 a heating rate of 1C/minand a transition temperature close to the isothermal testtemperature used in this procedure.10.2 Calibrate the mass signal from the apparatus accordingto Test Method E2040.NOTE 7Regular analysis of performance standards (materials ofknown mass loss characteristics) where ava
39、ilable,6serves as a check oninstrument status, operator efficiency, etc., and provides for a comparisonof results from different laboratories. Verify mass measurement confor-mity to better than 1 %. Verify time measurement conformity to betterthan 1 %.10.3 Calibrate the time signal from the apparatu
40、s accordingto Test Method E1860.NOTE 8For SCAQMD Rule 1144 purposes, calibrate the mass signalevery week, the temperature signal every three months, and the time signalevery six months.11. ProcedureNOTE 9For SCAQMD Rule 1144 purposes, additional proceeduresmay be required by the agency.11.1 Obtain a
41、 suitable baseline correction.11.2 Set the furnace and flow parameters.NOTE 10For SCAQMD Rule 1144 purposes, the total flow must be50 mL/min, divided (balance protection flow:sample purge flow) either10:40 mL/min or 20:30 mL/min.11.3 Cool the specimen test area of the apparatus to ambienttemperature
42、. For the purpose of this test, ambient temperatureis 35C or lower.NOTE 11Cooling of the specimen test area to 25C following anexperiment is time consuming on some apparatus. To improve productiv-ity, it is possible with some test samples to initiate the experiment at asomewhat higher temperature. T
43、his must be done with caution sincevolatility is a function of temperature. For highly volatile materials,appreciable portions of the test specimen mass may be lost in experimentalset up, if initiated at too high of a temperature.NOTE 12For SCAQMD Rule 1144 purposes, initial temperature is25 6 2C.11
44、.4 With the apparatus closed in the normal operatingposition, tare the balance so that the empty sample panindicates zero mass.11.5 Open the apparatus to expose the specimen holder.11.6 Carefully place 10 6 1 mg of the test specimen on thespecimen holder. Other specimen sizes may be used but mustbe
45、indicated in the report.NOTE 13Care should be taken to ensure that the sample is free of airbubbles.NOTE 14For SCAQMD Rule 1144 purposes, specimen size is10 6 1 L, autosamplers are not to be used and the specimen must bedistributed evenly over the bottom of the specimen holder.11.7 Close the apparat
46、us and record the initial mass as mi.Ifthe apparatus has provisions for direct recording of masspercent, adjust it to read 100 %.NOTE 15Should the test specimen have appreciable volatility atambient temperature, it may lose a significant amount of mass as it isplaced into the test position. In such
47、cases, care should be taken to perform11.6 and 11.7 as quickly as is practical.11.8 Heat the test specimen at 5C/min to the isothermal testtemperature, while recording specimen mass (or mass percent),temperature and elapsed time. Other heating rates may be used,but must be indicated in the report.NO
48、TE 16Selection of the optimum operating parameters of isothermaltest temperature and test time (tt) is dependent on the class of materialsbeing tested. The technique of response surface methodology (RSM) maybe useful in predicting optimum operating parameters.7,8Some commonexperimental conditions ar
49、e presented in Tables 1 and 2.NOTE 17For SCAQMD Rule 1144 purposes, heating rate is 25C/minand isothermal test temperature is 81C.11.9 Once the isothermal test temperature is reached, it isheld there for the remainder of the experiment. The time fromstart to the isothermal portion of the experiment is taken as ti.11.10 After 5 min at the isothermal test temperature, thespecimen temperature may be recorded.11.11 The experiment is terminated in one of two ways.These termination criteria are identified as Test Method A andTest Method B.6Perfor
