1、Designation:D718420Standard Test Method forUltra Low Nitrogen in Aromatic Hydrocarbons by OxidativeCombustion and Reduced Pressure ChemiluminescenceDetection1This standard is issued under the fixed designation D7184;the number immediately following the designation indicates the year oforiginal adopt
2、ion or,in the case of revision,the year of 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 totalnitrogen in aromatic hydrocar
3、bons,such as benzene,toluene,and xylene.1.2 This test method is applicable to samples with nitrogenconcentrations up to 1.2 mg/kg.The Limit of Detection(LOD)is 0.04 mg/kg N and the Limit of Quantitation(LOQ)is 0.13mg/kg N.For higher nitrogen concentrations refer to TestMethod D4629.With careful anal
4、ytical technique,this methodcan be used to successfully analyze concentrations below thecurrent scope(see Appendix X1).NOTE1LOD and LOQ were calculated using data inASTM ResearchReport RR:D16-1044.1.3 In determining the conformance of the test results usingthis method to applicable specifications;re
5、sults shall berounded off in accordance with the rounding-off method 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 wit
6、h its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.For specific hazard statements,see Section 9.1.6 This international standard was developed in acc
7、or-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM S
8、tandards:2D3437 Practice for Sampling and Handling Liquid CyclicProductsD4629 Test Method for Trace Nitrogen in Liquid Hydrocar-bons by Syringe/Inlet Oxidative Combustion and Chemi-luminescence DetectionD6809 Guide for Quality Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Rel
9、ated Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 Other Documents:OSHA Regulations,29 CFR paragraphs 1910.1000 and1910.120033.Terminology
10、3.1 Definitions:3.1.1 oxidative pyrolysis,na process in which a sampleundergoes combustion in an oxygen rich environment attemperatures greater than 900C.3.1.2 pyrolytic decomposition,ncombusting a compoundto decompose it to carbon dioxide,water and elemental oxides.3.1.3 reduced pressure chemilumin
11、escence,na chemicalreaction at pressure less than 760 mm mercury(Hg)in whichlight is emitted.4.Summary of Test Method4.1 A specimen is introduced into a carrier gas stream,at acontrolled rate,and incorporated into a high temperaturefurnace(900 to 1150C)where an excess of oxygen is added.1This test m
12、ethod is under the jurisdiction of ASTM Committee D16 onAromatic,Industrial,Specialty and Related Chemicals and is the direct responsi-bility of Subcommittee D16.04 on Instrumental Analysis.Current edition approved June 1,2020.Published June 2020.Originallyapproved in 2007.Last previous edition appr
13、oved in 2019 as D7184 19.DOI:10.1520/D7184-20.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact 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.
14、Government Printing Office Superintendent of Documents,732 N.Capitol St.,NW,Mail Stop:SDE,Washington,DC 20401,http:/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.Unite
15、d StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers t
16、o Trade(TBT)Committee.Pyrolysis converts hydrocarbons in the specimen to carbondioxide and water.Organic nitrogen and inorganic nitrogencompounds,present in the specimen,are converted to nitricoxide(NO).Nitric oxide reacts with ozone in the detectorproducing nitrogen dioxide molecules in an excited state.Asthe excited nitrogen dioxide molecules relax to ground state,light is emitted.This light is detected by a photomultiplier tubeor by a photodiode with the resulting signal proportional to theco