ASTM_D_3054_-_98.pdf

Designation:D 3054 98Standard Test Methods forAnalysis of Cyclohexane by Gas Chromatography1This standard is issued under the fixed designation D 3054;the number immediately following the designation indicates the year oforiginal adoption or,in the case of 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.Scope1.1 These test methods cover the determination of thehydrocarbon impurities typically found in cyclohexane and thepurity of cyclohexane by difference by gas chromatography.Typical impurities in high purity cyclohexane are listed inTable 1.1.2 These test methods are applicable to impurity concen-trations in the range of 0.0001 to 0.1000 wt%and forcyclohexane purities of 98%or higher when using the internalstandard procedure.1.3 The following applies to all specified limits in this testmethod:for purposes of determining conformance with thistest method,an observed value or a calculated value shall berounded off to the nearest unit in the last right-hand digit usedin expressing the specification limit,in accordance with therounding-off method of Practice E 29.1.4 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 standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.For specific hazardstatements,see Note 2 and Section 7.2.Referenced Documents2.1 ASTM Standards:D 3437 Practice for Sampling and Handling Liquid CyclicProducts2E 29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications3E 260 Practice for Packed Column Gas Chromatography3E 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3E 1510 Practice for Installing Fused Silica Open TubularCapillary Columns in Gas Chromatographs32.2Other Document:OSHA Regulations,29 CFR,Paragraphs 1910.1000 and1910.120043.Summary of Test Methods3.1 Test Method A:Internal Standard ProcedureThisprocedure is used when the impurities are at 0.00010 to 0.1000wt%levels.A known amount of internal standard is added tothe sample.A portion of the sample is injected into thechromatograph and the levels of impurities are calculatedrelative to the amount of internal standard added.The amountof measured impurities,including benzene,is subtracted from100.00 to establish the purity of the cyclohexane samples.3.2 Test Method B:Straight Normalization ProcedureAportion of the sample is injected into the chromatograph using1These test methods are under the jurisdiction of ASTM Committee D16 onAromatic Hydrocarbons and Related Chemicals and are the direct responsibility ofSubcommittee D16.01 on Benzene,Toluene,Xylenes,Cyclohexane,and TheirDerivatives.Current edition approved Aug.10,1998.Published October 1998.Originallypublished as D 3054 93.Last previous edition D 3054 95.2Annual Book of ASTM Standards,Vol 06.04.3Annual Book of ASTM Standards,Vol 14.02.4Available from Superintendent of Documents,U.S.Government PrintingOffice,Washington,DC 20004.TABLE 1 Impurities Known or Suggested to be Present inCommercial CyclohexaneC4(1)n-butane(2)isobutaneC5(3)n-pentane(4)isopentane(5)cyclopentaneC6(6)n-hexaneA(7)2-methylpentane(8)3-methylpentane(9)methylcyclopentaneA(10)benzeneA(11)2,2-dimethylbutane(12)2,3-dimethylbutaneC7(13)3,3-dimethylpentane(14)2,3-dimethylpentane(15)1,1-dimethylcyclopentane(16)1,t3-dimethylcyclopentane(17)1,t2-dimethylcyclopentane(18)1,c2-dimethylcyclopentane(19)2,2-dimethylpentane(20)2,4-dimethylpentane(21)1,c3-dimethylcyclopentane(22)ethylcyclopentane(23)methylcyclohexaneA(24)3-ethylpentane(25)3-methylhexane(26)2-methylhexane(27)n-heptaneAThese components were used to prepare the standards used in the roundrobin program.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.a microlitre syringe at the specified conditions of the testmethod.The area of all the peaks and main component areelectronically integrated.These areas are normalized to100.00%.4.Significance and Use4.1 These test methods are suitable for establishing contractspecifications on cyclohexane and for use in internal qualitycontrol where cyclohexane is either produced or used in amanufacturing process.They may also be used in developmentor research work.Purity is commonly reported by subtractingthe determined impurities from 100.00.However,a gas chro-matographic analysis can not determine absolute purity ifunknown components are contained within the material beingexamined.NOTE1In case of dispute,the internal standard procedure will be thecorrect procedure to use.5.Apparatus5.1 Gas Chromatograph(GC)(for a Fused SilicaColumn)A multi-ramp temperature,programmable GC builtfor capillary column chromatography.It must have a flameionization detector and a split injection sy