1、Designation: D 3760 08Standard Test Method forAnalysis of Isopropylbenzene (Cumene) by GasChromatography1This standard is issued under the fixed designation D 3760; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. 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 the purityof isopropylbenzene (cumene) by gas chromatography.1.2 This test me
3、thod has been found applicable to themeasurement of impurities such as nonaromatic hydrocarbons,benzene, ethylbenzene, t-butylbenzene, n-propylbenzene,alpha-methylstyrene, sec-butylbenzene, and diisopropylben-zene, which are common to the manufacturing process ofisopropylbenzene. Limit of detection
4、for these impurities is 10mg/kg (see 5.1).1.3 In determining the conformance of the test results usingthis method to applicable specifications, results shall berounded off in accordance with the rounding-off method ofPractice E29.1.4 This standard does not purport to address all of thesafety concern
5、s, 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 7.2. Referenced Documents2.1 ASTM Standar
6、ds:2D 3437 Practice for Sampling and Handling Liquid CyclicProductsD 6809 Guide for Quality Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE 260 Practice for Pac
7、ked Column Gas ChromatographyE 355 Practice for Gas Chromatography Terms and Rela-tionshipsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE 1510 Practice for Installing Fused Silica Open TubularCapillary Columns in Gas Chromatographs2.2 Other Documen
8、t:OSHA Regulations, 29 CFR, paragraphs 1910.1000 and1910.120033. Summary of Test Method3.1 A known amount of internal standard is added to asample of isopropylbenzene. The prepared sample is mixedand analyzed by a gas chromatograph equipped with a flameionization detector (FID). The peak area of eac
9、h impurity andthe internal standard is measured and the amount of eachimpurity is calculated from the ratio of the peak area of theinternal standard versus the peak area of the impurity. Purity byGC (the isopropylbenzene content) is calculated by subtractingthe sum of the impurities found from 100.0
10、0. Results arereported in weight percent.4. Significance and Use4.1 This test method is suitable for setting specifications onthe materials referenced in 1.2 and for use as an internal qualitycontrol tool where isopropylbenzene is produced or is used ina manufacturing process. It may also be used in
11、 developmentor research work involving isopropylbenzene.4.2 This test method is useful in determining the purity ofisopropylbenzene with normal impurities present includingdiisopropylbenzenes. If extremely high boiling or unusualimpurities are present in the isopropylbenzene, this test methodwould n
12、ot necessarily detect them and the purity calculationwould be erroneous.4.3 Cumene hydroperoxide, if present, will yield decompo-sition products that will elute in the chromatogram therebygiving incorrect results.4.4 The nonaromatic hydrocarbons commonly present fromthe isopropylbenzene manufacturin
13、g process will interfere withthe determination of benzene when Column A in Table 1 isused.1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibility ofSubcommittee D16.07 on Styrene, Ethylbenzene and C9 and C10 Ato
14、maticHydrocarbons.Current edition approved Jan. 1, 2008. Published January 2008. Originallyapproved in 1979. Last previous edition approved in 2002 as D 3760 02e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book
15、 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., NW, Mail Stop: SDE, Washington, DC 20401, http:/www.access.gpo.gov.1*A Summary of Changes section appe
16、ars at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.5 The internal standard must be sufficiently resolved fromany impurity and the isopropylbenzene peak.5. Apparatus5.1 Gas ChromatographAny instrument hav
17、ing a flameionization detector that can be operated at the conditions givenin Table 1. The system should have sufficient sensitivity toobtain a minimum peak height response for 10 mg/kgn-butylbenzene of twice the height of the signal backgroundnoise.5.2 ColumnsThe choice of column is based on resolu
18、tionrequirements. Any column may be used that is capable ofresolving all significant impurities from isopropylbenzene andfrom the internal standard. The columns described in Table 1have been used successfully.5.3 RecorderElectronic integration is recommended.6. Reagents and Materials6.1 Purity of Re
19、agentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused, provide
20、d it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.1.1 Internal StandardNormal Butylbenzene (nBB) isthe recommended internal standard of choice. Other com-pounds may be found acceptable provided they meet th
21、ecriteria as defined in 4.5 and 6.1.6.2 Carrier GasChromatographic grade helium or hydro-gen is recommended.6.3 Compressed AirChromatographic grade.6.4 HydrogenHigh purity.7. Hazards7.1 Consult current OSHA regulations and suppliers Mate-rial Safety Data Sheets on handling materials listed in this t
22、estmethod.8. Sampling and Handling8.1 Sample the material in accordance with PracticeD 3437.9. Preparation of Apparatus9.1 Follow manufacturers instructions for mounting andconditioning the column into the chromatograph and adjustingthe instrument to the conditions described in Table 1 allowingsuffi
23、cient time for the equipment to reach equilibrium. SeePractices E 260, E 1510 and E 355 for additional informationon gas chromatography practices and terminology.10. Procedure10.1 Into a 100-mL volumetric flask, add 100 L of nBB to99.90 mL of cumene. Mix well. Assuming a density of 0.856for nBB and
24、0.857 for cumene, the resulting nBB concentrationwill be 0.1000 weight %.10.2 Inject into the gas chromatography an appropriateamount of sample as previously determined according to 6.1and start the analysis.10.3 Obtain a chromatograph and peak integration report.Fig. 1 and Fig. 2 illustrate a typic
25、al analysis of cumene forColumns A and B, respectively.11. Calculations11.1 Determine the area defined by each peak in thechromatogram.11.2 Calculate the percent concentration of the total nonaro-matics and each impurity as follows:Ci5Ai!C2!A2!(1)where:Ci= concentration of component i, weight %,Ai=
26、peak area of component i,A2= peak area of nBB,C2= concentration of nBB, weight %.11.3 Calculate the total concentration of all impurities asfollows:Ct5 (Ci(2)where:Ct= total concentration of all impurities.11.4 Calculate the purity of isopropylbenzene as follows:isopropylbenzene, weight % 5 100.000
27、2 Ct(3)12. Report12.1 Report the individual impurities to the nearest0.0001 %.12.2 Report the purity of isopropylbenzene to the nearest0.001 weight%.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notl
28、isted 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, Inc. (USPC), Rockville,MD.TABLE 1 Typical Instrumental ParametersColumn A Column BDetector Fla
29、me Ionization Flame IonizationColumn:Tubing fused silica fused silicaStationary phase polyethylene glycol methyl siliconeSolid support crosslinked crosslinkedFilm thickness 0.25 0.5 Length, m 50 50Diameter, mm 0.32 mm ID 0.32 mm IDTemperatures:Injector, C 275 275Detector, C 300 300Oven:Initial, C 60
30、 35Time 1, min 10 10Final, C 175 275Rate, C/min 10 5Time 2, min 10 0Carrier gas hydrogen heliumFlow rate, mL/min 1.0 1.0Split ratio 100:1 100:1Sample size, L 1.0 1.0D376008213. Precision and Bias513.1 PrecisionThe following criteria should be used tojudge the acceptability of results obtained by thi
31、s test method(95 % confidence level). The precision criteria were derivedfrom round robin testing of four samples. Results of theinterlaboratory study data were analyzed in accordance withPractice E 691.13.1.1 Intermediate PrecisionDuplicate results by thesame operator should not be considered suspe
32、ct unless theydiffer by more than the amount listed in Table 2 and Table 3.13.1.2 ReproducibilityThe results between two laborato-ries should not be considered suspect unless they differ bymore than the 6 amounts listed in Table 2 and Table 3.13.2 BiasSince there is no accepted reference materialsui
33、table for determining the bias for the procedure in this testmethod for measuring isopropylbenzene purity, bias has notbeen determined.14. Quality Guidelines14.1 Refer to Guide D 6809 for suggested QA/QC activitiesthat can be used as part of this test method. It is recommendedthat the operator of th
34、is test method select and perform relevantQA/QC activities like the ones in Guide D 6809 to help ensurethe quality of the data generated by this test method.15. Keywords15.1 alpha methylstyrene; analysis by gas chromatography;benzene; butylbenzene; cumene; ethylbenzene; isopropylben-zene; nonaromati
35、c hydrocarbons; propylbenzene5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D161032.FIG. 1 Typical Chromatogram using Conditions for Column AD3760083FIG. 2 Typical Chromatogram using Conditions for Column BD3760084TABLE 2 Typi
36、cal Values for Intermediate Precision (formerlycalled Repeatability) and Reproducibility for Selected CumeneComponentsComponentConcentration,wt %Repeatability Reproducibilitya-Methylstyrene 0.0065 0.0003 0.00060.0083 0.0007 0.00100.0104 0.0012 0.0014Benzene 0.0024 0.00023 0.00088Ethylbenzene 0.0042
37、0.0004 0.00300.0080 0.0008 0.00380.0099 0.0009 0.0042Nonaromatics 0.0163 0.0009 0.00480.0571 0.0050 0.0063n-Propylbenzene 0.0192 0.0018 0.00170.0218 0.0010 0.00130.0246 0.0001 0.0009s-Butylbenzene 0.0024 0.0002 0.00220.0037 0.0002 0.00310.0059 0.0004 0.0044t-Butylbenzene 0.0067 0.0003 0.00090.0106 0
38、.0004 0.00130.0283 0.0010 0.0035Cumene 99.8443 0.0046 0.088899.8657 0.0062 0.075299.9221 0.0106 0.039299.9386 0.0119 0.0287TABLE 3 Intermediate Precision (formerly called Repeatability)and ReproducibilityCumeneRepeatability = 0.07801 (3 ) 7.7843Reproducibility = 0.63789(3) + 63.7785t-ButylbenzeneRep
39、eatability = 0.031894(3 ) + 0.00009Reproducibility = 0.120596(3) + 0.0000648s-ButylbenzeneRepeatability = 0.054069(3 ) + 0.0000437Reproducibility = 9.60703(3) + 0.000817n-PropylbenzeneRepeatability = 0.30407(3 ) + 0.007613Reproducibility = 0.14927(3) + 0.004605a-MethylstyreneRepeatability = 0.21785(
40、3 ) 0.0010752Reproducibility = 0.20833(3) 0.000761BenzeneRepeatability = 0.095(3 )Reproducibility = 0.367175(3)NonaromaticsRepeatability = 0.098932(3 ) 0.000697Reproducibility = 0.03733(3) + 0.004214EthylbenzeneRepeatability = 0.099441(3 ) 0.000045Reproducibility = 0.208332(3) + 0.0021557D3760085SUM
41、MARY OF CHANGESCommittee D16 has identified the location of selected changes to this standard since the last issue(D 3760 - 02e1) that may impact the use of this standard. (Approved January 1, 2008.)(1) 1.4 Revised statement.(2) Section 2 Revised format of footnotes and addedadditional references an
42、d renumbered sections according to theEditorial Guidelines.(3) Section 13 Revised definitions, corrected Table 2.(4) Section 14 Added new section.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of
43、 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 and must be reviewed every five
44、 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 of theresponsible technical co
45、mmittee, 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 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).D3760086
