1、Designation: D3760 13Standard Test Method forAnalysis of Isopropylbenzene (Cumene) by GasChromatography1This standard is issued under the fixed designation D3760; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. 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 the purityof isopropylbenzene (cumene) by gas chromatography.1.2 This test metho
3、d has been found applicable to themeasurement of impurities such as nonaromatic hydrocarbons,benzene, ethylbenzene, t-butylbenzene, n-propylbenzene,alpha-methylstyrene, sec-butylbenzene, anddiisopropylbenzene, which are common to the manufacturingprocess of isopropylbenzene. Limit of detection for t
4、heseimpurities is 10 mg/kg (see 5.1). This method has been foundapplicable for concentrations of various components up to 571ppm.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 metho
5、d 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, associated with its use. It is theresponsibility of the user of this standard
6、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 Standards:2D3437 Practice for Sampling and Handling Liquid CyclicProductsD6809 Guide for Quality
7、 Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE260 Practice for Packed Column Gas ChromatographyE355 Practice for Gas Chromatography Terms and Relation-shipsE6
8、91 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1510 Practice for Installing Fused Silica Open TubularCapillary Columns in Gas Chromatographs2.2 Other Document:OSHA Regulations, 29 CFR paragraphs 1910.1000 and1910.120033. Summary of Test Method3.1 A kno
9、wn 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 each impurity andthe internal standard is measured and the amount of eachimpurity is calculated fro
10、m 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 100.00. Results arereported in weight percent.4. Significance and Use4.1 This test method is suitable
11、 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 developmentor research work involving isopropylbenzene.4.2 This test method is useful in determ
12、ining the purity ofisopropylbenzene with normal impurities present includingdiisopropylbenzenes. If extremely high boiling or unusual1This test method is under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and is the direct responsibility ofSubcommittee D16.07
13、on Styrene, Ethylbenzene and C9 and C10 AromaticHydrocarbons.Current edition approved June 1, 2013. Published June 2013. Originallyapproved in 1979. Last previous edition approved in 2012 as D3760 12. DOI:10.1520/D3760-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontac
14、t 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., NW, Mail Stop: SDE, Washington, DC 20401, h
15、ttp:/www.access.gpo.gov.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1impurities are present in the isopropylbenzene, this test methodwould not necessarily detect them
16、 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 manufacturing process will interfere w
17、iththe determination of benzene when Column A in Table 1 isused.4.5 The internal standard must be sufficiently resolved fromany impurity and the isopropylbenzene peak.5. Apparatus5.1 Gas ChromatographAny instrument having a flameionization detector that can be operated at the conditions givenin Tabl
18、e 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 resolutionrequirements. Any column may be used that is capable ofresolving all significa
19、nt impurities from isopropylbenzene andfrom the internal standard. The columns and conditions de-scribed in Table 1 have been used successfully and shall beused as referee in cases of dispute.5.3 RecorderElectronic integration is recommended.6. Reagents and Materials6.1 Purity of ReagentsReagent gra
20、de 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, provided it is first asc
21、ertained 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 thecriteria as defi
22、ned in 4.5 and 6.1.6.2 Carrier Gas, Makeup, and Detector GasesHelium,hydrogen, nitrogen, or other carrier, makeup and detector gases99.999 % minimum purity. Oxygen in carrier gas less than 1ppm, less than 0.5 ppm is preferred. Purify carrier, makeup,and detector gases to remove oxygen, water, and hy
23、drocarbons.6.3 Compressed AirPurify air to remove water and hydro-carbons. Air for an FID should contain less than 0.1 ppm THC.6.4 Pure Compounds for CalibrationThe purity of allreagents should be 99.9 % or greater. If the purity is less than99 %, the concentration and identification of impurities m
24、ustbe known so that the composition of the standard can beadjusted for the presence of the impurities.7. Hazards7.1 Consult current OSHA regulations and suppliers Mate-rial Safety Data Sheets on handling materials listed in this testmethod.8. Sampling and Handling8.1 Sample the material in accordanc
25、e with Practice D3437.9. 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 allowingsufficient time for the equipment to reach equilibrium. SeePractice E1510 f
26、or more information on column installation.See Practice E355 for additional information on gas chroma-tography practices and terminology.10. Procedure10.1 Into a 100-mL volumetric flask, add 100 L of nBB to99.90 mL of cumene sample. Mix well. Assuming a density of0.856 for nBB and 0.857 for cumene,
27、the resulting nBBconcentration will be 0.1000 weight %.10.2 Inject into the gas chromatography an appropriateamount of sample sufficient to satisfy the sensitivity conditionsas detailed in 5.1 and start the analysis.10.3 Obtain a chromatograph and peak integration report.Fig. 1 and Fig. 2 illustrate
28、 a typical analysis of cumene forColumns A and B, respectively.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals,
29、BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.TABLE 1 Recommended Operating ConditionsColumn A Column BDetector Flame Ionization Flame IonizationColumn:Tubing fused silica fused silicaStationary phase
30、 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 35Time 1, min 10 10Final, C 175 275Rate, C/min 10 5Time 2, min 10 0Carrier gas hydro
31、gen heliumFlow rate, mL/min 1.0 1.0Split ratio 100:1 100:1Sample size, L 1.0 1.0D3760 13211. 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= concentra
32、tion of component i, weight %,Ai= 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:isop
33、ropylbenzene, weight % 5 100.000 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%.13. Precision and Bias513.1 PrecisionThe following criteria should be used tojudge the acceptability of results obtain
34、ed by this test method(95 % confidence level). The precision criteria were derivedfrom an ILS that was conducted using the conditions listedunder Column B in Table 1 which included nine laboratoriesanalyzing four samples in triplicate. Practice E691 was fol-lowed for the design and analysis of the d
35、ata; the details aregiven in ASTM Research Report RR:D16-1032.13.1.1 Intermediate Precision (formerly calledRepeatability)Results should not be suspect unless theydiffer by more than the amount listed in Table 2 and Table 3.Results differing by less than “r” have a 95 % probability ofbeing correct.5
36、Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D16-1032.FIG. 1 Typical Chromatogram using Conditions for Column AD3760 133FIG. 2 Typical Chromatogram using Conditions for Column BD3760 13413.1.2 ReproducibilityResults submitted
37、by two labsshould not be considered suspect unless they differ by morethan that shown in Table 2 and Table 3. Results differing byless than “R” have a 95 % probability of being correct.TABLE 2 Typical Values for Repeatability (r) and Reproducibility(R) for Selected Cumene Components Using the Condit
38、ions inColumn B of Table 1ComponentConcentration,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 0.0004 0.00300.0080 0.0008 0.00380.0099 0.0009 0.0042Nonaromatics 0.0163 0.0009 0.00480.0571
39、 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 0.0004 0.00130.0283 0.0010 0.0035Cumene 99.8443 0.0046 0.088899.8657 0.0062 0.075299.9221 0.0
40、106 0.039299.9386 0.0119 0.0287TABLE 3 Intermediate Precision (formerly called Repeatability)and ReproducibilityCumeneRepeatability = 0.07801() 7.7843Reproducibility = 0.63789() + 63.7785t-ButylbenzeneRepeatability = 0.031894() + 0.00009Reproducibility = 0.120596() + 0.0000648s-ButylbenzeneRepeatabi
41、lity = 0.054069() + 0.0000437Reproducibility = 9.60703() + 0.000817n-PropylbenzeneRepeatability = 0.30407() + 0.007613Reproducibility = 0.14927() + 0.004605a-MethylstyreneRepeatability = 0.21785() 0.0010752Reproducibility = 0.20833() 0.000761BenzeneRepeatability = 0.095( )Reproducibility = 0.367175(
42、)NonaromaticsRepeatability = 0.098932() 0.000697Reproducibility = 0.03733() + 0.004214EthylbenzeneRepeatability = 0.099441() 0.000045Reproducibility = 0.208332() + 0.0021557D3760 13513.2 BiasSince there is no accepted reference materialsuitable for determining the bias for the procedure in this test
43、method for measuring isopropylbenzene purity, bias has notbeen determined.14. Quality Guidelines14.1 Laboratories shall have a quality control system inplace.14.1.1 Confirm the performance of the test instrument ortest method by analyzing a quality control sample followingthe guidelines of standard
44、statistical quality control practices.14.1.2 A quality control sample is a stable material isolatedfrom the production process and representative of the samplebeing analyzed.14.1.3 When QA/QC protocols are already established inthe testing facility, these protocols are acceptable when theyconfirm th
45、e validity of test results.14.1.4 When there are no QA/QC protocols established inthe testing facility, use the guidelines described in GuideD6809 or similar statistical quality control practices.15. Keywords15.1 alpha methylstyrene; analysis by gas chromatography;benzene; butylbenzene; cumene; ethy
46、lbenzene; isopropylben-zene; nonaromatic hydrocarbons; propylbenzeneSUMMARY OF CHANGESCommittee D16 has identified the location of selected changes to this standard since the last issue (D3760-12)that may impact the use of this standard. (Approved June 1, 2013.)(1) Revisions were made in 10.1 and 10
47、.2. (2) Reference correction was made in 10.2.Committee D16 has identified the location of selected changes to this standard since the last issue (D3760 - 08)that may impact the use of this standard. (Approved December 15, 2012.)(1) Section 1 Updated to current Editorial Guidelines.(2) Section 6 Upd
48、ated to current Editorial Guidelines.(3) Section 9 Updated to current Editorial Guidelines.(4) Section 13 Updated to current Editorial Guidelines.(5) Section 14 Updated to current Editorial Guidelines.(6) Table 1 and Table 2 Headers updated to current EditorialGuidelines.ASTM International takes no
49、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 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 eit
