1、Designation: D3760 13D3760 18Standard 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
2、last revision. 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 purity of isopropylbenzene (cumene) by gas chromatography.1.2 This t
3、est method has been found applicable to the measurement of impurities such as nonaromatic hydrocarbons, benzene,ethylbenzene, t-butylbenzene, n-propylbenzene, alpha-methylstyrene, sec-butylbenzene, and diisopropylbenzene, which arecommon to the manufacturing process of isopropylbenzene. Limit of The
4、 limit of quantitation for these impurities averages 0.0030wt.% based on the data in Table 2, while the limit of detection for these impurities is 10 mg/kg (see averages 0.0010 wt.%. 5.1).This method has been found applicable for concentrations of various components up to 571 ppm.0.0571 wt.%.1.3 In
5、determining the conformance of the test results using this method to applicable specifications, results shall be roundedoff in accordance with the rounding-off method of Practice E29.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this
6、standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limi
7、tations prior to use. For specific hazard statements, see Section 7.1.6 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommenda
8、tions issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D3437 Practice for Sampling and Handling Liquid Cyclic ProductsD6809 Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related Mat
9、erialsE29 Practice for Using Significant Digits in Test Data to Determine Conformance with SpecificationsE260 Practice for Packed Column Gas ChromatographyE355 Practice for Gas Chromatography Terms and RelationshipsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a
10、 Test MethodE1510 Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs2.2 Other Document:OSHA Regulations, 29 CFR paragraphs 1910.1000 and 1910.1200 33. Summary of Test Method3.1 Aknown amount of internal standard is added to a sample of isopropylbenzene. The pre
11、pared sample is mixed and analyzedby a gas chromatograph equipped with a flame ionization detector (FID). The peak area of each impurity and the internal standardis measured and the amount of each impurity is calculated from the ratio of the peak area of the internal standard versus the peak1 This t
12、est method is under the jurisdiction of ASTM Committee D16 on Aromatic Hydrocarbons Aromatic, Industrial, Specialty and Related Chemicals and is the directresponsibility of Subcommittee D16.07 on Styrene, Ethylbenzene and C9 and C10 Aromatic Hydrocarbons.Current edition approved June 1, 2013Jan. 1,
13、2018. Published June 2013January 2018. Originally approved in 1979. Last previous edition approved in 20122013 asD3760 12.D3760 13. DOI: 10.1520/D3760-13.10.1520/D3760-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annu
14、al Book of ASTM Standardsvolume information, refer to the standardsstandards Document Summary page on the ASTM website.3 Available 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.This document is
15、 not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropr
16、iate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*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 States
17、1area of the impurity. Purity by GC (the isopropylbenzene content) is calculated by subtracting the sum of the impurities found from100.00. Results are reported in weight percent.4. Significance and Use4.1 This test method is suitable for setting specifications on the materials referenced in 1.2 and
18、 for use as an internal qualitycontrol tool where isopropylbenzene is produced or is used in a manufacturing process. It may also be used in development orresearch work involving isopropylbenzene.4.2 This test method is useful in determining the purity of isopropylbenzene with normal impurities pres
19、ent includingdiisopropylbenzenes. If extremely high boiling or unusual impurities are present in the isopropylbenzene, this test method wouldnot necessarily detect them and the purity calculation would be erroneous.4.3 Cumene hydroperoxide, if present, will yield decomposition products that will elu
20、te in the chromatogram thereby givingincorrect results.4.4 The nonaromatic hydrocarbons commonly present from the isopropylbenzene manufacturing process will interfere with thedetermination of benzene when Column A in Table 1 is used.4.5 The internal standard must be sufficiently resolved from any i
21、mpurity and the isopropylbenzene peak.5. Apparatus5.1 Gas ChromatographAny instrument having a flame ionization detector that can be operated at the conditions given inTable 1. The system should have sufficient sensitivity to obtain a minimum peak height response for 10 mg/kg n-butylbenzene oftwice
22、the height of the signal background noise.5.2 ColumnsThe choice of column is based on resolution requirements.Any column may be used that is capable of resolvingall significant impurities from isopropylbenzene and from the internal standard. The columns and conditions described in Table 1have been u
23、sed successfully and shall be used as referee in cases of dispute.5.3 RecorderElectronic integration is recommended.Chromatographic data systems are preferred but electronic integrationmay be used if the user can demonstrate that the results are consistent with the precision statement. Recorders are
24、 not consideredadequate for meeting the precision requirements of this standard.6. Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the Committee on Analy
25、tical Reagents of the American Chemical Society, wheresuch specifications are available.4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently highpurity to permit its use without lessening the accuracy of the determination.4 Reagent Chemicals, American Chem
26、ical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S.
27、Pharmacopeial Convention, Inc. (USPC), Rockville, MD.TABLE 1 Recommended Operating ConditionsColumn A Column BDetector Flame Ionization Flame IonizationColumn:Tubing fused silica fused silicaStationary phase polyethylene glycol methyl siliconeSolid support crosslinked crosslinkedFilm thickness 0.25
28、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 hydrogen heliumFlow rate, mL/min 1.0 1.0Split ratio 100:1 100:1Sample size, L 1.0 1.0D3760 1826.1.
29、1 Internal StandardNormal Butylbenzene (nBB) is the recommended internal standard of choice. Other compounds maybe found acceptable provided they meet the criteria as defined in 4.5 and 6.1.6.2 Carrier Gas, Makeup, and Detector GasesHelium, hydrogen, nitrogen, or other carrier, makeup and detector g
30、ases 99.999% minimum purity. Oxygen in carrier gas less than 1 ppm, less than 0.5 ppm is preferred. Purify carrier, makeup, and detector gasesto remove oxygen, water, and hydrocarbons.6.3 Compressed AirPurify air to remove water and hydrocarbons. Air for an FID should contain less than 0.1 ppm THC.6
31、.4 Pure Compounds for CalibrationThe purity of all reagents should be 99.9 % or greater. If the purity is less than 99 %,the concentration and identification of impurities must be known so that the composition of the standard can be adjusted for thepresence of the impurities.7. Hazards7.1 Consult cu
32、rrent OSHA regulations and suppliers Material Safety Data Sheets on handling materials listedsuppliersSafetyData Sheets, and local regulations for all materials used in this test method.8. Sampling and Handling8.1 Sample the material in accordance with Practice D3437.9. Preparation of Apparatus9.1 F
33、ollow manufacturersmanufacturers instructions for mounting and conditioning the column into the chromatograph andadjusting the instrument to the conditions described in Table 1 allowing sufficient time for the equipment to reach equilibrium. SeePractice E1510 for more information on column installat
34、ion. See Practice E355 for additional information on gas chromatographypractices and terminology.10. Procedure10.1 Into a 100-mLvolumetric flask, add 100 Lof nBB to 99.90 mLof cumene sample. Mix well.Assuming a density of 0.856for nBB and 0.857 for cumene, the resulting nBB concentration will be 0.1
35、000 weight %.10.2 Inject into the gas chromatography an appropriate amount of sample sufficient to satisfy the sensitivity conditions asdetailed in 5.1 and start the analysis.10.3 Obtain a chromatograph and peak integration report. Fig. 1 and Fig. 2 illustrate a typical analysis of cumene for Column
36、sA and B, respectively.11. Calculations11.1 Determine the area defined by each peak in the chromatogram.11.2 Calculate the percent concentration of the total nonaromatics and each impurity as follows:Ci 5Ai!C2!A2!(1)where:Ci = concentration of component i, weight %,Ai = peak area of component i,A2 =
37、 peak area of nBB,C2 = concentration of nBB, weight %.11.3 Calculate the total concentration of all impurities as follows:Ct 5(Ci (2)where:Ct = total concentration of all impurities.11.4 Calculate the purity of isopropylbenzene as follows:isopropylbenzene,weight %5100.0002Ct (3)12. Report12.1 Report
38、 the individual impurities to the nearest 0.0001 %.0.0001 weight %.12.2 Results less than the LOD should be reported as 0.0003 weight %.12.3 Report the purity of isopropylbenzene to the nearest 0.0010.01 weight%.D3760 18313. Precision and Bias513.1 PrecisionThe following criteria should be used to j
39、udge the acceptability of results obtained by this test method (95 %confidence level). The precision criteria were derived from an ILS that was conducted using the conditions listed under ColumnB in Table 1 which included nine laboratories analyzing four samples in triplicate. Practice E691 was foll
40、owed for the design andanalysis of the data; the details are given in ASTM Research Report RR:D16-1032.13.1.1 Intermediate Precision (formerly called Repeatability)Results should not be suspect unless they differ by more thanthe amount listed in Table 2 and Table 3. Results differing by less than “r
41、” have a 95 % probability of being correct.13.1.2 ReproducibilityResults submitted by two labs should not be considered suspect unless they differ by more than thatshown in Table 2 and Table 3. Results differing by less than “R” have a 95 % probability of being correct.13.2 BiasSince there is no acc
42、epted reference material suitable for determining the bias for the procedure in this test methodfor measuring isopropylbenzene purity, bias has not been determined.14. Quality Guidelines14.1 Laboratories shall have a quality control system in place.14.1.1 Confirm the performance of the test instrume
43、nt or test method by analyzing a quality control sample following theguidelines of standard statistical quality control practices.14.1.2 Aquality control sample is a stable material isolated from the production process and representative of the sample beinganalyzed.14.1.3 When QA/QC protocols are al
44、ready established in the testing facility, these protocols are acceptable when they confirmthe validity of test results.5 Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D16-1032. Contact ASTM CustomerService serviceastm.org.FIG
45、. 1 Typical Chromatogram using Conditions for Column AD3760 184FIG. 2 Typical Chromatogram using Conditions for Column BD3760 18514.1.4 When there are no QA/QC protocols established in the testing facility, use the guidelines described in Guide D6809 orsimilar statistical quality control practices.T
46、ABLE 2 Typical Values for Repeatability (r) and Reproducibility(R) for Selected Cumene Components Using the Conditions inColumn B of Table 1Component Concentration,wt % Repeatability ReproducibilityComponent Concentration,wt % Repeatability Reproducibilitya-Methylstyrene 0.0065 0.0003 0.00060.0083 0
47、.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 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
48、.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 0.0106 0.039299.9386 0.0119 0.0287TABLE 3 Intermediate Precision (formerly called Repeatability)and ReproducibilityCumeneRepeatab
49、ility = 0.07801() 7.7843Reproducibility = 0.63789() + 63.7785t-ButylbenzeneRepeatability = 0.031894() + 0.00009Reproducibility = 0.120596() + 0.0000648s-ButylbenzeneRepeatability = 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()NonaromaticsRepeatability = 0.098932() 0.0006
