ASTM_D_8301_-_21.pdf

Designation:D830121Standard Test Method forDetermination of the Content of Nitroxide Radical(4-Hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl)in Butadiene,Styrene and Isoprene by Cyclic Voltammetry Method1This standard is issued under the fixed designation D8301;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()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method is designed to determine the content ofnitroxide radical 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl(H-Tempo)in butadiene,isoprene,and styrene.1.2 This test method is applicable to samples with nitroxideradical 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl(H-Tempo)with concentrations to 100 mgkg.The limit ofdetection(LOD)is 0.47 mg/kg for nitroxide radical 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl(H-Tempo)and the limitof quantitation(LOQ)is 1.6 mg/kg nitroxide radical4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl(H-Tempo).1.3 The following applies for the purposes of determiningthe conformance of the test results using this test method toapplicable specifications,results shall be rounded of in accor-dance with the rounding-off method of Practice 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 to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-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 Standards:2D1193 Specification for Reagent WaterE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications2.2 Other Documents:OSHA Regulations,29 CFR,paragraph 1910.1000 Air Con-taminants3OSHA Regulations,29 CFR,paragraph 1910.1200 HazardCommunication33.Summary of Test Method3.1 A sample of butadiene is dissolved in acetonitrile.Butadiene is separated by evaporation.The intensity of thecathode current signal is compared in the cyclic voltammetry(CV)with that produced by the known concentration of theH-Tempo.3.2 A sample of isoprene and styrene is dissolved inacetonitrile.The intensity of the cathode current signal iscompared in the cyclic voltammetry(CV)with that producedby the known concentration of the H-Tempo.4.Significance and Use4.1 Nitroxide radicals(H-Tempo,O-Tempo(4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl),etc.)are widely used as inhibi-torsofthermopolymerizationintheprocessesoftransportation,storage,and separation of monomers(isoprene,butadiene,styrene,etc.).This test method provides a procedurefor assaying nitroxide radicals in monomers.1This test method is under the jurisdiction of ASTM Committee D16 onAromatic,Industrial,Specialty and Related Chemicals and is the direct responsi-bility of Subcommittee D16.07 on Styrene,Ethylbenzene and C9 and C10AromaticHydrocarbons.Current edition approved June 1,2021.Published June 2021.DOI:10.1520/D8301-21.2For 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.Government Printing Office,Superintendent ofDocuments,732 N.Capitol St.,NW,Washington,DC 20401-0001,http:/www.access.gpo.gov.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United 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 to Trade(TBT)Committee.14.2 This procedure can be used for determination of thecontent of nitroxide radicals(H-Tempo,O-Tempo,etc.)inother solvents(dimethyl formamide,DMSO etc.).5.Interferences5.1 The N-phenyl-p-phenylenediamine derivatives in con-centrations of 1 mg/kg interfere with the determination of thenitroxide radical concentration by this procedure.5.2 Do not use rubber stoppers as antioxidants on thesurface of the rubber contaminate acetonitrile solution.Theseantioxidants at concentrations of 1 mg/kg interfere with deter-mination of the nitroxide radical concentration.6.Apparatus6.1 Laboratory balances with maximum weighing capacityof 200 g and 500 g,capable of dete