1、Designation:D 4534 99Standard Test Method forBenzene Content of Cyclic Products by GasChromatography1This standard is issued under the fixed designation D 4534;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision
2、.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the ben-zene content of specific cyclic hydrocarbon products.1.2 Benzene may be determined
3、 over a range from 5 to 300mg/kg.1.3 The products in which benzene can be determinedinclude cyclohexane,toluene,individual C8aromatics,cumene,and styrene.1.4 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
4、 standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.A specific hazardstatement is given in Section 7.2.Referenced Documents2.1 ASTM Standards:D 3437 Practice for Sampling and Handling Liquid CyclicProducts2E 260 Prac
5、tice for Packed Column Gas Chromatography3E 355 Practice for Gas Chromatography Terms and Rela-tionships32.2Other Document:OSHA Regulations,29 CFR,paragraphs 1910.1000 and1910.120043.Summary of Test Method3.1 A gas chromatograph with a flame ionization or otherdetector and a column containing a supp
6、orted polar liquidphase is used.A reproducible volume of sample is injected.Quantitative results are obtained from the measured area of therecorded benzene peak by using a factor obtained from theanalysis of a blend of known benzene content.4.Significance and Use4.1 Knowledge of the benzene content
7、is typically requiredfor cyclic products used as chemical intermediates and sol-vents.This test method may be used for final product inspec-tions,process control,establishing specifications,and researchwork.5.Apparatus5.1 Gas ChromatographAny chromatograph having ei-ther a flame ionization or other
8、detector that is capable ofproviding a minimum peak height response of 0.1 mV for 20mg/kg benzene using a maximum sample injection of 2 L.5.2 Chromatographic ColumnThe choice of column isbased on resolution requirements.Any column may be used ifit is capable of resolving benzene from the major compo
9、nentand other impurities.The column described in Table 1 has beenfound satisfactory.5.3 IntegratorElectronic integration is recommended.5.4 Recorder,Strip Chart,0 to 1-mV range recordingpotentiometer with a response time of 1 s or less and maximumnoise level of 0.3%of full scale.If electronic integr
10、ation is notused,a minimum chart width of 200 mm and a minimum chartspeed of 1 cm/min is required.5.5 Microsyringe,10-L capacity.5.6 Volumetric Flask,50-mL capacity.6.Reagents and Materials6.1 Carrier Gas,helium or nitrogen,chromatographicgrade.6.2 Hydrogen,zero grade.6.3 Compressed Air,oil free.6.4
11、 Benzene,99%minimum purity.6.5 Specific Cyclic Hydrocarbon,high-purity(best gradeobtainable)benzene content not to exceed 10%of the levelexpected in the sample.7.Hazards7.1 Consult current OSHA regulations,suppliers Material1This test method is under the jurisdiction of ASTM Committee D16 onAromatic
12、 Hydrocarbons and Related Chemicals and is the direct responsibility ofSubcommittee D16.04 on Instrumental Analysis.Current edition approved June 10,1999.Published August 1999.Originallypublished as D 4534 85.Last previous edition D 4534 89(1993)1.2Annual Book of ASTM Standards,Vol 06.04.3Annual Boo
13、k of ASTM Standards,Vol 14.02.4Available from Superintendent of Documents,U.S.Government PrintingOffice,Washington,DC 20402.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.Safety Data Sheets,and local regulations for all materials usedin
14、this test method.8.Sampling8.1 Guidelines for taking samples from bulk are given inPractice D 3437.9.Calibration9.1 Prepare a calibration blend or blends of benzene in thespecific cyclic hydrocarbon at the level or levels approximatingthose in the samples to be analyzed.A separate blend must bemade
15、for each specific cyclic hydrocarbon.9.2 Calculate the benzene content of the calibration blendusing the following equation and the densities listed in Table 2.Benzene,mg/kg 5B1!B2!S1!S2!103!(1)where:B1=density of benzene,B2=volume of benzene added to the cyclic hydrocarbon,L,S1=density of cyclic hy
16、drocarbon,andS2=volume of cyclic hydrocarbon,mL.9.3 For example,to prepare an 81-mg/kg blend of benzenein toluene,fill a 50-mL volumetric flask to the mark withhigh-purity toluene.With a microsyringe,carefully add 4.0 Lof benzene to the toluene and mix well.9.4 Analyze both the blend and the pure cyclic hydrocarbonused to prepare the blend as described in Section 10.Subtractthe area of the benzene found in the pure cyclic hydrocarbonfrom the area of the benzene in the blend to determine the area
