1、Designation: E 2403 06Standard Test Method forSulfated Ash of Organic Materials by Thermogravimetry1This standard is issued under the fixed designation E 2403; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This standard describes the determination of sulfatedash content (sometimes called residue-on-ignition) of organicmaterials by t
3、hermogravimetry. The method converts commonmetals found in organic materials (such as sodium, potassium,lithium, calcium, magnesium, zinc, and tin) into their sulfatesalts permitting estimation of their total content as sulfates oroxides. The range of the test method is from 0.1 to 100 % metalconten
4、t.1.2 SI values are the standards.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 to determine theapplicability of regulatory limit
5、ations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 874 Test Method for Sulfated Ash from Lubricating Oilsand AdditivesD 914 Test Methods for EthylcelluloseD 3516 Test Methods for Ashing CelluloseE 473 Terminology Relating to Thermal Analysis and Rhe-ologyE 1131 Test Method for Composit
6、ional Analysis by Ther-mogravimetryE 1142 Terminology Relating to Thermophysical PropertiesE 1582 Practice for Calibration of Temperature Scale forThermogravimetryE 2040 Test Method for Mass Scale Calibration of Thermo-gravimetric Analyzers2.2 Other StandardsThe United States Pharmacopeia XXII and T
7、he NationalFormulary XVII, United States Pharmacopeial Conven-tion, Rockville, MD, 1990, Section 281, p.1527.3. Terminology3.1 Definitions: Technical terms used in this standard aredefined in Terminologies E 473 and E 11423.1.1 sulfated ash, nthe residue remaining after a speci-men has been oxidized
8、, and the residue subsequently treatedwith sulfuric acid and heated to constant weight.3.1.2 residue-on-ignition, ROI, na commonly used aliasfor sulfated ash.3.1.3 volatiles, nfor the purpose of this test, those mate-rials evolving as gas at temperatures below 160 C in an airatmosphere.4. Summary of
9、 Test Method4.1 A test specimen is ignited and burned in an air atmo-sphere at temperatures up to 600 C until only ash remains.After cooling, the residue is treated with sulfuric acid andheated to 800 C to constant weight. The residue remaining isidentified as sulfated ash.4.2 This test method is si
10、milar to D 874 for lubricating oilsand additives, D 914 for ethyl cellulose, D 3516 cellulose, andthat of the U.S. Pharmacopeia and makes use of thermogravi-metric apparatus to perform the determination.5. Significance and Use5.1 The sulfated ash may be used to indicate the level ofknown metal-conta
11、ining additives or impurities in an organicmaterial. When phosphorus is absent, barium, calcium, mag-nesium, sodium and potassium are converted to their sulfates.Tin and zinc are converted to their oxides.5.2 This standard may be used for research and develop-ment, specification acceptance and quali
12、ty assurance purposes.6. Interferences6.1 If phosphorus is present with metals, it partially orwholly remains in the sulfated ash as metal phosphates.6.2 Sulfur and chlorides do not interfere.1This test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct re
13、sponsibility of Subcommittee E37.01 on Thermaland Rheological Test Methods and Practices.Current edition approved March 1, 2006. Published April 2006. Originallyapproved in 2004. Last previous edition approved in 2004 as E 2403 04.2For referenced ASTM standards, visit the ASTM website, www.astm.org,
14、 orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Apparatus7.1
15、 Thermogravimetric Analyzer (TGA)The essential in-strumentation required to provide the minimum thermogravi-metric analytical capability for this standard includes:7.1.1 A thermobalance composed of:7.1.1.1 A furnace to provide uniform controlled heating of aspecimen to a constant temperature of 850
16、C and at a constantrate of 5 to 60 C/min7.1.1.2 A temperature sensor to provide an indication of thespecimen or furnace temperature to 6 1 C.7.1.1.3 A continuously recording balance to measure thespecimen mass with a minimum capacity of 50 mg and asensitivity of 6 0.01 mg.7.1.1.4 A means of maintain
17、ing the specimen or containerunder atmospheric control of air at a purge flow rate of 50 to100 mL/min 6 5 mL/min.7.1.2 A temperature controller capable of executing a spe-cific temperature program by operating the furnace betweenselected temperature limit at a rate of 5 to 60 C/min and to anisotherm
18、al temperature of up to 850 C which is maintainedconstant to 6 10 C for a minimum of 70 minutes.7.1.3 A recording device, capable of recording and display-ing any fraction of the specimen mass signal (TGA curve)including signal noise.7.1.4 Containers (pans, crucibles, etc.) that are inert to thespec
19、imen and to concentrated sulfuric acid and that will remaingravimetrically stable up to 850 C. Platinum is a commonmaterial of construction for this purpose.7.2 Graduated micropipette with capacity of 40-50 L8. Reagents and Materials8.1 Sulfuric acid, concentrated (98%), with a relative den-sity of
20、1.84 (Warning Poison. Corrosive. Strong Oxidizer).8.2 AirZero grade or better purity9. Hazards9.1 Sulfuric acid may be corrosive to some thermogravimet-ric apparatus. A regular visual inspection of the apparatus willdetermine if any corrosion is taking place.9.2 The exhausted purge gas from the appa
21、ratus will containsulfuric acid fumes. This purge gas shall be treated byexhausting to a acid hood or by bubbling through a solution ofsodium bicarbonate to absorb the acidic fumes.10. Preparation of Apparatus10.1 After turning the power on, allow the instrument toequilibrate for at least one hour p
22、rior to any measurements.10.2 Perform any cleaning and calibration procedures de-scribed by the manufacturer in the apparatus OperatorsManual.11. Calibration and Standardization11.1 Perform temperature calibration of the thermogravi-metric analyzer according to E 1582 using reference materialssuitab
23、le for the temperature range of this method, namely 25 to800 C.11.2 Perform mass calibration of the thermogravimetricanalyzer according to E 2040.12. Procedure12.1 Transfer 30 to 40 mg of the sample into a tared, clean,and dry sample container. Assemble the thermogravimetricanalyzer for operation. R
24、ecord the initial weight of the testspecimen as Woto within 6 0.01 mgNOTE 1The sample container may be preconditioned by heating in anair atmosphere to 800 C.NOTE 2Smaller quantities of test specimen will reduce the quantifi-cation capability of this method.12.2 Heat the specimen from ambient to 600
25、 C at 10C/min under an air purge gas with a flow rate of 50 to 100 65 mL/min and record the thermal curve.12.3 Cool the heated sample and thermogravimetric appa-ratus to 20 to 25 C.12.4 If desired, record the weight at 150 C (Wv) as the massafter apparent loss of volatiles. Record the weight at 600
26、C asthe mass of the residue (Wr).NOTE 3Mass loss due to apparent loss of volatiles at 150 C andresidue at 600 C are not required for the sulfated ash determination butmay be recorded for additional sample characterization (see standardE 1131.)NOTE 4The temperature at which the mass loss due to volat
27、iles isdetermined may range from 100 to 160 C depending upon the material.Other values may be used but shall be reported.12.5 Using a micropipette, add 30 40 L of 98 % gradesulfuric acid to the sample residue (in the container). Reas-semble the instrument for operation.12.6 Heat the specimen from am
28、bient to 800 C at 50C/min and hold isothermally at 800 6 25 C for 60 6 1minutes under an air purge at 50 to 100 6 5 mL/min.12.7 Cool the heated specimen and thermogravimetric ap-paratus to 20 to 25 C.12.8 Record the residue mass Ws.12.9 Calculate percent Sulfated Ash (S) using Eq 1.12.10 In the abse
29、nce of interferences and if the specificmetal in the test specimen is known, then its mass percent (M)may be calculated by multiplying the sulfated ash value by thefactors presented in Table 1 using Eq 2.12.11 If desired, calculate the Percent Volatiles (V) andPercent Residue (R) using equations 3 a
30、nd 4, respectively.13. Calculation13.1 Sulfated Ash (S) may be determined using the follow-ing equation:S 5 Ws3 100%/Wo(1)TABLE 1 Sulfated Ash FactorsMetal Sulfated Ash FactorSodium (Na) Na2SO40.3237Potassium (K) K2SO40.4487Lithium (Li) Li2SO40.1263Calcium (Ca) CaSO40.2944Magnesium (Mg) MgSO40.2019Z
31、inc (Zn) ZnO 0.8034Tin (Sn) SnO 0.8812E2403062where:S = Sulfated ash, mass %Ws= Mass of sulfated ash from Section 12.8,mgWo= Original mass of the test specimen from Section 12.1,mg.13.2 If the specific metal in the test specimen is known andif this is the only metal ion present, then its mass percen
32、t (M)may be calculated by multiplying the sulfated ash value by thefactors presented in Table 1 using Eq 2.M metal! 5 Factor 3 S (2)where:M = Percent of the identified metal, mass %14. Report14.1 Report the sulfated ash (S) to three significant figures.14.2 Report to three significant figures the pe
33、rcent metal(M) when desired and the metal is known.14.3 Provide a copy of the original thermal curve.14.4 The specific dated version of this test method used.15. Precision and Bias15.1 An interlaboratory study was conducted in 2005 inwhich lithium cyclohexanebutyrate and calcium oxalate mono-hydrate
34、 were tested. Eight laboratories participated in the testusing seven instrument models from two manufacturers. AResearch Report is available from ASTM Headquarters.315.2 Precision:15.2.1 Within laboratory variability may be described usingthe repeatability value (r) obtained by multiplying the repea
35、t-ability standard deviation by 2.8. The repeatability valueestimates the 95 % confidence limit. That is, two results fromthe same laboratory should be considered suspect (at the 95 %confidence level) if they differ by more than the repeatabilityvalue.15.2.1.1 The within laboratory repeatability sta
36、ndard devia-tion for lithium in lithium cyclohexanebutyrate was 0.057 %(RSD of 1.5 %) with 20 degrees of experimental freedom.15.2.1.2 The within laboratory repeatability standard devia-tion for calcium in calcium oxalate monohydrate was 0.24 %(RSD of 0.92 %) with 20 degrees of experimental freedom.
37、15.2.2 Between laboratory variability may be describedusing the reproducibility value (R) obtained by multiplying thereproducibility standard deviation by 2.8. The reproducibilityvalues estimates the 95 % confidence limit. That is, two resultsobtained from different laboratories, operators or appara
38、tusshould be considered suspect (at the 95 % confidence level) ifthey differ by more than the reproducibility value.15.2.2.1 The between laboratory reproducibility standarddeviation for lithium in lithium cyclohexanebutyrate was0.10 % (RSD = 2.5 %) with 20 degrees of experimentalfreedom.15.2.2.2 The
39、 between laboratory reproducibility standarddeviation for calcium in calcium oxalate monohydrate was0.32 % (RSD = 1.2 %) with 20 degrees of experimentalfreedom.15.3 Bias:15.3.1 Bias is the difference between the mean value ob-tained and an accepted reference value for the same material.15.3.1.1 The
40、lithium cyclohexanebutyrate used in this studywas supplied (by Sigma-Aldrich, St. Louis, MO) with aCertificate of Analysis indicate an ICP assay of 3.9 % lithium.The sample is 3.94 % lithium by formula weight.15.3.1.2 The mean value for lithium in lithium cyclohex-anebutyrate characterized by this m
41、ethod was found to be3.93 %, indicating no detectable bias in this method.16. Keywords16.1 ash; residue on ignition; sulfated ash; thermogravimet-ric analysis; thermogravimetryASTM International takes no position respecting the validity of any patent rights asserted in connection with any item menti
42、onedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee a
43、nd must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting
44、of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Bo
45、x C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: E371036.E2403063
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