1、Designation: D6526 10Standard Test Method forAnalysis of Toluene by Capillary Column GasChromatography1This standard is issued under the fixed designation D6526; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. 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 covers the determination of hydrocar-bon impurities typically found in, and the purity of, samplescontaining
3、98 wt % and greater toluene. This test method isapplicable to impurity concentrations in the range of 0.0005 to1.6 wt %.1.2 Monocyclic aromatic hydrocarbons containing 6through 8 carbon atoms, cumene, 1,4dioxane, and nonaro-matic aliphatic hydrocarbons containing up to 12 carbon atomscan be detected
4、 by this test method. The nonaromatic com-pounds are determined as a composite.1.3 The following applies to all specified limits in this testmethod: for purposes of determining conformance with thistest method, an observed value or a calculated value shall berounded off “to the nearest unit” in the
5、last right-hand digitused in expressing the specification limit, in accordance withthe rounding-off method of Practice E29.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of
6、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. For specific hazardstatements, see Section 9.2. Referenced Document
7、s2.1 ASTM Standards:2D3437 Practice for Sampling and Handling Liquid CyclicProductsD4790 Terminology ofAromatic Hydrocarbons and RelatedChemicalsD6809 Guide for Quality Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE29 Practice for Using Significant Digits i
8、n Test Data toDetermine Conformance with SpecificationsE355 Practice for Gas Chromatography Terms and Rela-tionshipsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1510 Practice for Installing Fused Silica Open TubularCapillary Columns in Gas Chromato
9、graphs2.2 Other Document:OSHA Regulations, 29 CFR paragraphs 1910.1000 and1910.120033. Terminology3.1 See Terminology D4790 for definitions of terms used inthis test method.4. Summary of Test Method4.1 A portion of the sample is injected into a gas chromato-graph using a microlitre syringe at the sp
10、ecified conditions ofthe test method. The toluene and other components areseparated as they are transported through the column by aninert carrier gas. The components in the effluent are measuredby a flame ionization detector (FID). The area of the impuritypeaks and toluene are electronically integra
11、ted. The peak areasare corrected with effective carbon number (ECN)4responsefactors and normalized to 100.0000 %.5. Significance and Use5.1 This test method is suitable for determining the concen-trations of known impurities in refined toluene and for use as1This test method is under the jurisdictio
12、n of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibility ofSubcommittee D16.01 on Benzene, Toluene, Xylenes, Cyclohexane and TheirDerivatives.Current edition approved June 1, 2010. Published June 2010. Originallyapproved in 2000. Last previous edition ap
13、proved in 2003 as D6526 - 031. DOI:10.1520/D6526-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Availabl
14、e from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:/www.access.gpo.gov.4Scanlon, J. T., and Willis, D. E., “Calculation of Ionization Detector RelativeResponse Factors Using the Effective Carbon Number Concept,” Journ
15、al ofChromatographic Science, Vol 35, August, 1985, pp. 333-339.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.an integral quality control tool where toluene is produ
16、ced orused in manufacturing.5.2 Toluene purity is reported, but a chromatographic analy-sis cannot determine absolute purity if unknown or undetectedcomponents are present in the sample.6. Interferences6.1 If present, nonaromatic hydrocarbons of 13 carbons orgreater, alcohols, ethers, and other simi
17、lar organic compoundscan interfere with this test method by co-eluting with thearomatic hydrocarbons.6.2 Compounds not detected by a FID are not determined bythis test method.6.3 Nonvolatile material is not determined.7. Apparatus7.1 Gas Chromatograph (GC)any GC built for capillarycolumn chromatogra
18、phy. The system shall have sufficientsensitivity, linearity, and range to obtain a minimum peakheight response for 0.0010 wt % impurity of twice the height ofthe signal background noise, while not exceeding the full scaleof either the detector or the electronic integration for the majorcomponent. It
19、 shall have a split injection system that will notdiscriminate over the boiling range of the samples analyzed.The system should be capable of operating at conditions givenin Table 1.7.2 Recorderelectronic integration is recommended.7.3 Capillary Columnfused silica capillary column with1,2,3-tris-2-c
20、yano-ethoxypropane (TCEP) phase is recom-mended. Polyethylene glycol (PEG) columns have been suc-cessfully used. Other columns may be used after it has beenestablished that such a column is capable of separating allmajor impurities under operating conditions appropriate for thecolumn.7.4 Microsyring
21、ecapable of delivering 1 L of sample.8. Reagents8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. It is intended that all reagents shall conform tothe specifications of the Committee on Analytical Reagents ofthe American Chemical Society,5where such specifications areavailable
22、, unless otherwise indicated. Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.8.2 Carrier GasHelium, 99.99 mole % minimum, is rec-ommended.8.3 FID Detector Gases:8.3.1 Hydrog
23、en99.99 mole % minimum.8.3.2 Airless than 10 ppm each of total hydrocarbons andwater.9. Hazards9.1 Consult current OSHA regulations, suppliers MaterialSafety Data Sheets, and local regulations for all materials usedin this test method.10. Sample Handling10.1 Collect the samples in accordance with Pr
24、acticeD3437.10.2 To preserve sample integrity (consistency) and preventthe loss of volatile components, which may be in somesamples, do not uncover samples any longer than necessary.11. Preparation of Apparatus11.1 Follow the manufacturers instructions for mountingand conditioning the column in the
25、chromatograph.11.2 Adjust the instrument to the conditions as described inTable 1 to give the proper separations.Allow sufficient time forthe instrument to reach equilibrium as indicated by a stablebaseline. See Practices E355 and E1510 for additional infor-mation on gas chromatography practices and
26、 terminology.12. Procedure12.1 Inject an appropriate amount of specimen, typically 1.0L, into the chromatograph. A low purity toluene samplechromatogram, which shows the relative retention time ofcomponents typically found in commercial toluene, is illus-trated in Fig. 1.NOTE 1Since TCEP is a nonbon
27、ded phase, significant retention timeshifts can occur with column condition.12.2 Measure the area of all peaks. The nonaromaticsfraction includes all peaks eluting before benzene. Sum to-gether all nonaromatic peaks and report as a total area.5Reagent Chemicals, American Chemical Society Specificati
28、ons, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention,
29、Inc. (USPC), Rockville,MD.TABLE 1 Typical Instrumental ParametersDetector: Flame ionizationDetector temperature, C 150CColumn: 50 m by 0.25 mmTubing Fused silicaStationary phase TCEPFilm thickness, m 0.40Column temperature, C 70Carrier Gas HeliumLinear velocity at 70C, cm/s 25Inlet: SplitInjection p
30、ort temperature, C 150CSplit ratio 40Split flow, mL/min 55Sample size, L 1.0D6526 102FIG. 1 Low Purity Toluene Sample ChromatogramD652610313. Calculation13.1 Using the ECN weight response factors listed in Table2, calculate the concentration of each component as follows:Ci5 100 3 Ai3 Ri! /(i51nAi3 R
31、i! (1)where:Ci= concentration results for component(s) i, weight %,Ai= peak area of component(s) i, andRi= ECN response factor for component(s) i.14. Report14.1 Report the following information:14.1.1 Report impurity concentrations less than 0.0005 % as0.0005 %.14.1.2 Report greater than 0.0005 % ea
32、ch of the nonaromat-ics, benzene, ethylbenzene, xylenes, and cumene to the nearest0.0001 %.14.1.3 Report toluene purity to the nearest 0.01 %.15. Precision and Bias15.1 PrecisionThe following criteria should be used tojudge the acceptability of results obtained by this test method(95 % confidence le
33、vel). The precision criteria were derivedfrom six laboratories performing three analyses on threestandards over a two-day period. The results of the precisionstudy were calculated using Practice E691.15.1.1 Intermediate Precision (formerly calledRepeatability)Duplicated results obtained on the sames
34、ample in the same laboratory by the same operator on thesame instrument should not be considered suspect unless theydiffer by more than the intermediate precision value shown inTable 3.15.1.2 ReproducibilityDuplicated results obtained on thesame sample by different laboratories, with different opera
35、tors,different instruments, and at different times should not differ bymore than the reproducibility value listed in Table 3.15.1.3 BiasSystematic deviation of the method averagevalue or the measured value from an accepted reference value.Since the absolute purity of the toluene solvent could not be
36、determined, an absolute statement of bias could not be deter-mined from this study. An estimate of bias was made bypreparing three gravimetric standards with three differentconcentrations of impurities. The standards were then analyzedas unknowns in the interlaboratory study (see Table 4).16. Qualit
37、y Guidelines16.1 Laboratories shall have a quality control system inplace.16.1.1 Confirm the performance of the test instrument ortest method by analyzing a quality control sample followingthe guidelines of standard statistical quality control practices.16.1.2 A quality control sample is a stable ma
38、terial isolatedfrom the production process and representative of the samplebeing analyzed.16.1.3 When QA/QC protocols are already established inthe testing facility, these protocols are acceptable when theyconfirm the validity of test results.16.1.4 When there are no QA/QC protocols established inth
39、e testing facility, use the guidelines described in GuideD6809 or similar statistical quality control practices.17. Keywords17.1 benzene; gas chromatography; impurities; toluenepurity;1,4-dioxaneTABLE 2 Effective Carbon Number Response FactorsComponent Response Factor (Weight)Nonaromatics: 0.9975Ben
40、zene 0.9100Toluene 0.9200Ethylbenzene 0.9275p-Xylene 0.9275m-Xylene 0.9275o-Xylene 0.9275Cumene 0.93331,4-Dioxane 3.0800TABLE 3 Intermediate Precision and ReproducibilityActual(Weight %)IntermediatePrecisionReproducibilityNonAromaticStd #1 1.6314 0.0078 0.2024Std #2 0.9718 0.0039 0.1243Std #3 0.0207
41、 0.0022 0.0081BenzeneStd #1 0.0006 0.0001 0.0002Std #2 0.0010 0.0002 0.0003Std #3 0.0301 0.0008 0.0070TolueneStd #1 98.2688 0.0084 0.2142Std #2 98.9756 0.0042 0.1327Std #3 99.8967 0.0025 0.0272EthylBenzeneStd #1 0.0987 0.0015 0.0185Std #2 0.0506 0.0007 0.0116Std #3 0.0203 0.0007 0.00511,4dioxaneStd
42、#1 0.0005 0.0004 0.0008Std #2 0.0010 0.0007 0.0008Std #3 0.0302 0.0012 0.0079TABLE 4 Estimated BiasActual(weight %)Mean DifferenceNonAromaticStd #1 1.6314 1.6404 0.0090Std #2 0.9718 0.9854 0.0136Std #3 0.0207 0.0254 0.0047BenzeneStd #1 0.0006 0.0006 0.0000Std #2 0.0010 0.0011 0.0001Std #3 0.0301 0.0
43、286 0.0015TolueneStd #1 98.2688 98.2603 0.0085Std #2 98.9756 98.9615 0.0141Std #3 99.8967 99.8905 0.0062EthylBenzeneStd #1 0.0987 0.0984 0.0003Std #2 0.0506 0.0509 0.0003Std #3 0.0203 0.0204 0.00011,4dioxaneStd #1 0.0005 0.0005 0.0000Std #2 0.0010 0.0012 0.0002Std #3 0.0302 0.0321 0.0019D6526 104SUM
44、MARY OF CHANGESCommittee D16 has identified the location of selected changes to this standard since the last issue(D6526 - 031) that may impact the use of this standard. (Approved June 1, 2010.)(1) Section 1 Scope added statement on units. (2) Section 16 Quality Guidelines added.ASTM International t
45、akes no position respecting the validity of any patent rights asserted in connection with any item mentionedin 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
46、responsibility.This standard is subject to revision at any time by the responsible technical committee and 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 addr
47、essed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting 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
48、the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D6526 105
