1、Designation: D 6526 03e1Standard Test Method forAnalysis of Toluene by Capillary Column GasChromatography1This standard is issued under the fixed designation D 6526; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEEditorial change was made in 14.1.2 in June 2003.1. Scope*1.1 This test method covers the determination of hydrocar-bon impuriti
3、es typically found in, and the purity of, samplescontaining 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
4、hydrocarbons containing up to 12 carbon atomscan be detected 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 calcul
5、ated value shall berounded off “to the nearest unit” in the last right-hand digitused in expressing the specification limit, in accordance withthe rounding-off method of Practice E29.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is there
6、sponsibility 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 Documents2.1 ASTM Standards:D 3437 Practice for Sampling and Handling Li
7、quid CyclicProducts2D 4790 Terminology of Aromatic Hydrocarbons and Re-lated Chemicals2E29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications3E 355 Practice for Gas Chromatography Terms and Rela-tionships4E 691 Practice for Conducting an Interlaboratory St
8、udy toDetermine the Precision of a Test Method3E 1510 Practice for Installing Fused Silica Open TubularCapillary Columns in Gas Chromatographs42.2 Other Document:OSHA Regulations, 29 CFR, paragraphs 1910.1000 and1910.120053. Terminology3.1 See Terminology D 4790 for definitions of terms used inthis
9、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 specified conditions ofthe test method. The toluene and other components areseparated as they are transported through the column by aninert carrier gas. The compon
10、ents in the effluent are measuredby a flame ionization detector (FID). The area of the impuritypeaks and toluene are electronically integrated. The peak areasare corrected with effective carbon number (ECN)6responsefactors and normalized to 100.0000 %.5. Significance and Use5.1 This test method is s
11、uitable for determining the concen-trations of known impurities in refined toluene and for use as1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibility ofSubcommittee D16.01 on Benzene, Toluene, Xylenes, Cycloh
12、exane, and TheirDerivatives.Current edition approved Jan. 10, 2003. Published March 2003. Originallyapproved in 2000. Last previous edition approved in 2000 as D 6526 - 00.2Annual Book of ASTM Standards, Vol 06.04.3Annual Book of ASTM Standards, Vol 14.02.4Annual Book of ASTM Standards, Vol 03.06.5A
13、vailable from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401.6Scanlon, J. T., and Willis, D. E., “Calculation of Ionization Detector RelativeResponse Factors Using the Effective Carbon Number Concept,” Journal ofChromatographi
14、c 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 produced orused in manuf
15、acturing.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 similar organic compoun
16、dscan 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 chromatography. The system sha
17、ll have sufficientsensitivity, linearity, and range to obtain a minimum peakheight response for 0.0010 wt % impurity of twice the heightof the signal background noise, while not exceeding the fullscale of either the detector or the electronic integration for themajor component. It shall have a split
18、 injection system that willnot discriminate over the boiling range of the samples ana-lyzed. The system should be capable of operating at conditionsgiven in Table 1.7.2 Recorderelectronic integration is recommended.7.3 Capillary Columnfused silica capillary column with1,2,3-tris-2-cyano-ethoxypropan
19、e (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 Microsyringecapable of deliv
20、ering 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 oftheAmerican Chemical Society7, where such specifications areavailable, unless otherwis
21、e 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, isrecommended.8.3 FID Detector Gases:8.3.1 Hydrogen99.99 mole % mini
22、mum.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 PracticeD 3437.10.2 T
23、o 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 chromatograph.11.2
24、 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 E 355 and E 1510 for additional infor-mation on gas chromatography practices and terminology.12.
25、 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 nonbonded phase, signi
26、ficant 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.13. Calculation13.1 Using the ECN weight response factors listed in Table
27、2, calculate the concentration of each component as follows:Ci5 100 3 Ai3 Ri! /(i51nAi3 Ri! (1)7Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Sta
28、ndards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.TABLE 1 Typical Instrumental ParametersDetector: Flame ionizationDetector temperature, C 150CColumn: 50 m by 0.25 mmTubing
29、 Fused silicaStationary phase TCEPFilm thickness, m 0.40Column temperature, C 70Carrier Gas HeliumLinear velocity at 70C, cm/s 25Inlet: SplitInjection port temperature, C 150CSplit ratio 40Split flow, mL/min 55Sample size, L 1.0D652603e12FIG.1LowPurityTolueneSampleChromatogramD652603e13where:Ci= con
30、centration 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 % each of the nonaromat
31、-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 level). The precision
32、 criteria were derivedfrom six laboratories performing three analyses on threestandards over a two-day period. The results of the precisionstudy were calculated using Practice E 691.15.1.1 Intermediate Precision (formerly calledRepeatability)Duplicated results obtained on the samesample in the same
33、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 operators,different ins
34、truments, 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 bedetermined, an abs
35、olute 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. Keywords16.1 benzene; ga
36、s chromatography; impurities; toluenepurity;1,4-dioxaneTABLE 2 Effective Carbon Number Response FactorsComponent Response Factor (Weight)Nonaromatics: 0.9975Benzene 0.9100Toluene 0.9200Ethylbenzene 0.9275p-Xylene 0.9275m-Xylene 0.9275o-Xylene 0.9275Cumene 0.93331,4-Dioxane 3.0800D652603e14SUMMARY OF
37、 CHANGESCommittee D16 has identified the location of selected changes to this standard since the last issue(D 6526 - 00) that may impact the use of this standard.(1) Section 1.1 of the Scope was expanded to reflect the resultsof the interlaboratory study.(2) The statement “Polyethylene glycol column
38、s have beensuccessfully used” was added to Section 7.3.(3) The detection of impurities was lowered from 0.0010 to0.0005 % in Section14.1.1(4) The statement indicating to report “greater than 0.0010 to0.0005 % was changed to “greater than 0.0005 % in 14.1.2.(5) The Precision and Bias section was rewr
39、itten to include theinterlaboratory data.(6) A bias statement was added in Section 15.1.3.(7) Table 4 was added for estimated bias.TABLE 3 Intermediate Precision and ReproducibilityActual(Weight %)IntermediatePrecisionReproducibilityNonAromaticStd #1 1.6314 0.0078 0.2024Std #2 0.9718 0.0039 0.1243St
40、d #3 0.0207 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 0.00511,4
41、dioxaneStd #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
42、 0.0301 0.0286 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 0.0019D
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