1、Designation: D 5713 05Standard Test Method forAnalysis of High Purity Benzene for Cyclohexane Feedstockby Capillary Gas Chromatography1This standard is issued under the fixed designation D 5713; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of specificimpurities in, and the purity of benzen
3、e for cyclohexanefeedstock by gas chromatography.1.2 This test method has been found applicable to benzenein the range from 99 to 100 % purity and to impurities atconcentrations of 2 to 10 000 mg/kg.1.3 In determining the conformance of the test results usingthis method to applicable specifications,
4、 results shall berounded off in accordance with the rounding-off method ofPractice 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 thesafety concerns, if any, associat
5、ed 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 a specifichazard statement, see 7.1 and Section 8.2. Referenced Documents2.1 ASTM Standards:2D 3437
6、 Practice for Sampling and Handling Cyclic Prod-uctsD 4790 Terminology of Aromatic Hydrocarbons and Re-lated ChemicalsD 6809 Guide for Quality Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Co
7、nformance with SpecificationsE 260 Practice for Packed Column Gas ChromatographyE 355 Practices for Gas Chromatography Terms and Rela-tionshipsE 1510 Practice for Installing Fused Silica Open TubularCapillary Columns in Gas Chromatographs2.2 Other Document:OSHA Regulations,29CFR, paragraphs 1910.100
8、0 and1910.120033. Terminology3.1 Definitions:3.1.1 For definition of terms used in this test method seeTerminology D 4790.4. Summary of Test Method4.1 In this test method, the chromatogram peak area for eachimpurity is compared to the peak area of the internal standard(n-octane or other suitable kno
9、wn) added to the sample. Fromthe response factor of toluene relative to that of the internalstandard, and using a response factor of 1.00 for nonaromaticimpurities and the amount of internal standard added, theconcentrations of the impurities are calculated. The benzenecontent is obtained by subtrac
10、ting the total amount of allimpurities from 100.00.5. Significance and Use5.1 This test method is designed to obtain benzene purity onthe basis of impurities normally present in benzene and may beused for final product inspections and process control.5.2 This test method will detect the following im
11、purities:toluene, methylcyclopentane, n-hexane, 2-methylhexane, cy-clohexane, cyclopentane, 2-methylpentane, 2,3-dimethylpentane, 3-methylhexane, n-heptane, methylcyclohex-ane, ethylcyclopentane, 2,4-dimethylhexane, trimethylpentane,and others where specific impurity standards are available.Absolute
12、 purity cannot be accurately determined if unknownimpurities are present.6. Apparatus6.1 Gas ChromatographAny gas chromatograph having atemperature programmable oven, flame ionization detector and1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbon and Related Che
13、micals and is the direct responsibility ofSubcommittee D16.01 on Benzene, Toluene, Xylenes, Cyclohexane, and TheirDerivatives.Current edition approved July 1, 2005. Published August 2005. Originallyapproved in 1995. Last previous edition approved in 2000 as D 5713 00.2For referenced ASTM standards,
14、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.3Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St
15、., NW, Mail Stop: SDE, Washington, DC 20401.1*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.a splitter injector suitable for use with a fused silica capillarycolumn ma
16、y be used, provided the system has sufficientsensitivity that will give a minimum peak height of 3 times thebackground noise for 2 mg/kg of an impurity.6.2 ColumnFused silica capillary columns have beenfound to be satisfactory.An example is 50 m of 0.20-mm insidediameter fused silica capillary inter
17、nally coated to a filmthickness of 0.50 m with polydimethylsiloxane (see Table 1for suggested instrument parameters). Other columns may beused after it has been established that such a column is capableof separating all major impurities (for example, compoundslisted in 5.2) and the internal standard
18、 from the benzene underoperating conditions appropriate for the column. The columnmust give satisfactory resolution (distance from the valleybetween the peaks is not greater than 50 % of the peak heightsof the impurity) of cyclohexane from benzene as well as otherimpurity peaks. A poorly resolved pe
19、ak, such as cyclohexane,will often require a tangent skim from the neighboring peak.6.3 Electronic Integration, with tangent skim capabilities isrecommended.6.4 Vial.6.5 Microsyringes, assorted volumes.6.6 Injector, the specimen must be precisely and repeatedlyinjected into the gas chromatograph. An
20、 automatic sampleinjection device is highly recommended. Manual injection canbe employed if the precision stated in Table 2, IntermediatePrecision and Reproducibility, can be reliably and consistentlysatisfied.7. Reagents and Materials7.1 Carrier Gasa carrier gas (minimum purity of 99.95 %mol) appro
21、priate to the type of detector used should beemployed. (WarningIf hydrogen is used as the carrier gas,take special safety precautions to ensure that the system is freeof leaks and that the effluent is properly vented or burned.)7.2 Hydrogen, for the flame ionization detector (FID) mini-mum purity of
22、 99.999 % and 0.5 ppm total hydrocarbons ispreferred.7.3 Air, for the flame ionization detector, 0.1 ppm totalhydrocarbons is preferred.7.4 n-octane, 99.0 % minimum purity, or other internalstandard (99.0 % minimum purity), such as iso-octane, previ-ously analyzed to be free of compounds coeluting w
23、ithimpurities in the sample.NOTE 1It is highly recommended the carrier, make-up and detectorgases be purified to remove oxygen, water and hydrocarbons. It is alsorecommended the air be purified to remove hydrocarbons and water.8. Hazards8.1 Consult current OSHA regulations, suppliers MaterialSafety
24、Data Sheets, and local regulations for all materials usedin this test method.9. Sampling9.1 Sample in accordance with Practice D 3437.10. Preparation of Apparatus10.1 Follow the manufacturers instructions for mountingthe column into the chromatograph and adjusting the instru-ment to the desired cond
25、itions. Allow sufficient time for theequipment to reach equilibrium. See Practices E 260, E 355and E 1510 for additional information on gas chromatographyprocedures, terminology, and column installation. The columnand conditions in Table 1 were used to develp this analysis. Ifthere is a dispute, the
26、 column and conditions should be agreedupon between the parties or use Table 1 as a referee.11. Procedure11.1 Transfer approximately 10 g of the sample to beanalyzed to a tared vial and weigh to the nearest 0.1 mg. (MakeTABLE 1 Instrument Typical ParametersCarrier gas hydrogenLinear velocity at 40C,
27、 cm/s 40Detector flame ionizationDetector temperature, C 250CInjection port temperature, C 250CSplit ratio 40:1Split flow, mL/min 60Column 50mby0.20mmIDby0.5mbonded polydimethylsiloxanecapillary columnInitial column temperature, C 40Initial time, min 17Programming rate 10C/minFinal temperature, C 25
28、0CFinal time, min 10Sample size, L 1.2TABLE 2 Intermediate Precision and ReproducibilityComponentAverageConcentration ppmWeight %IntermediatePrecisionReproducibilityBenzene 99.9699.9799.960.0060.0070.0080.0220.0200.025Methylcyclopentane 10443548.312.22.527.919.415.1Toluene 6463285.13.01.822.016.69.1
29、Methylcyclohexane 13243797.41.43.234.85.417.0Methylcyclohexane + 196 7.9 54.9Toluene 10610612.94.433.620.4n-Hexane 4322.21.51.83.72.22.5n-Heptane 616152.71.54.011.15.623.4Ethylcyclopentane 76111.81.91.53.711.06.1Total Other Impurities 9910718522.544.655.5163.0190.6233.0D5713052sure that the sample i
30、s deposited in the center of the vial so thatthe liquid does not contact the neck.)11.2 Add approximately 0.1 g of internal standard (noctanewas used in Fig. 1) and quickly reweigh to the nearest 0.1 mg.(The internal standard is added to the vial while on the balancepan and deposited into the center
31、 of the liquidnot on the sideof the vial.)11.3 Cap the mixture and mix by inverting several times.11.4 Inject into the gas chromatograph an appropriateamount of the mixture as previously determined in accordancewith 6.1 and 6.2 and immediately start the analysis. (1.2 Lwas used in Fig. 1.)11.5 Deter
32、mine the areas of all the impurity peaks and theinternal standard. Identify the specific impurities by comparingthe chromatogram obtained to a typical chromatogram. (Uni-dentified impurities are summed and reported as a composite.)The chromatogram shown in Fig. 1 can be used for the columnand condit
33、ions specified in Table 1.12. Calculation12.1 Measure the areas of all peaks, including the internalstandard, except the benzene peak.12.2 Calculate the weight to milligram per kilogrammg/kg of the individual impurities, Cias follows:Ci5 106BDFGH(1)where:B = peak area of a specific impurity or group
34、 of impuri-ties,D = response factor, (see 12.3),F = mass of internal standard added to the sample, g,G = peak area of the internal standard,H = weight of sample before addition of internal stan-dard, g, and106= factor to convert to weight-mg/kg12.3 A response factor of 1.000 should be used for allhy
35、drocarbon impurities except toluene which will be 0.935.12.4 Calculate the benzene content by subtracting the sumof the impurities from 100.000. Benzene weight% = 100.000 (sum of impurities in weight %). Total impuri-ties are converted from mg/kg to weight percent by multiplyingby 0.0001 %.13. Repor
36、t13.1 Report the concentration of impurities to the nearestmg/kg and the benzene content to the nearest 0.01 %. Forconversion purposes, 1 mg/kg equals 0.0001 %.FIG. 1 High Purity BenzeneTypical Chromatogram(See Table 1)D571305314. Precision and Bias414.1 PrecisionThe following criteria should be use
37、d tojudge the acceptability (95 % probability level) of resultsobtained by this test method. The criteria in Table 2 werederived from an interlaboratory study between six laboratories.Three samples were analyzed in duplicate on two days.14.1.1 Intermediate Precision (formerly Repeatability)Results i
38、n the same laboratory should not be consideredsuspect unless they differ by more than the amounts shown inTable 2. On the basis of test error alone, the difference betweentwo results obtained in the same laboratory on the samematerial will be expected to exceed this value only 5 % of thetime.14.1.2
39、ReproducibilityResults submitted by each of twolaboratories should not be considered suspect unless they differby more than the amount shown in Table 2. On the basis of testerror alone, the difference between two test results obtained indifferent laboratories on the same material will be expected to
40、exceed this value only 5 % of the time.14.2 BiasSince there is no accepted reference materialsuitable for determining the bias for the procedure in this testmethod for measuring specific impurities, bias has not beendetermined.15. Quality Guidelines15.1 Refer to Guide D 6809 for suggested QA/QC acti
41、vitiesthat can be used as a part of this method. It is recommendedthat the operator of this method select and perform relevantQA/QC activities like the ones in Guide D 6809 to help ensurethe quality of data generated by this method.16. Keywords16.1 benzene; cyclohexane feedstock; impuritiesSUMMARY O
42、F CHANGESCommittee D16 has identified the location of selected changes to this standard since the last issue(D 5713 00) that may impact the use of this standard.(1) Substituted “polydimethylsiloxane” for column name in 6.2and Table 1.(2) Added Preparation of Apparatus section.(3) Added Quality Guide
43、lines section.(4) Added specifications for Gases in Section 7.ASTM International takes 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
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46、ir 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 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).4Supporting data are available from ASTM International Headquarters. RequestRR: D16-1018.D5713054
