ASTM_D_4768_-_11_2019.pdf

Designation:D476811(Reapproved 2019)Standard Test Method forAnalysis of 2,6-Ditertiary-Butyl Para-Cresol and 2,6-Ditertiary-Butyl Phenol in Insulating Liquids by GasChromatography1This standard is issued under the fixed designation D4768;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 covers the determination by gaschromatography of 2,6-ditertiary-butyl para-cresol and 2,6-ditertiary-butyl phenol in new and used insulating liquids atconcentrations up to 0.5%.It includes the determination inType I and II insulating mineral oils as specified in Specifica-tion D3487,but has also been used to measure these inhibitorsin other insulating liquids,such as esters and high fire-pointhydrocarbons.1.2 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.1.3 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:2D923 Practices for Sampling Electrical Insulating LiquidsD3487 Specification for Mineral Insulating Oil Used inElectrical ApparatusD5222 Specification for High Fire-Point Mineral ElectricalInsulating OilsE260 Practice for Packed Column Gas Chromatography3.Summary of Test Method3.1 The test specimen is placed onto a column containingactivated alumina and extracted to remove interfering sub-stances.The inhibitors are then eluted from the column withsuitable solvent and analyzed by gas chromatography.Theinhibitor type and quantity are determined by comparison ofeach component with a working standard tested under similarconditions.4.Significance and Use4.1 In new electrical insulating oil,this test method providesa quantitative measure of the amounts of 2,6-ditertiary-butylpara-cresol and 2,6-ditertiary-butyl phenol that have beenadded to the oil.In a used oil,the test measures the amount ofthese inhibitors remaining in the oil.This test method issuitable for manufacturing control,specification acceptance,and service evaluation.4.2 This test method is used to separate,identify,andquantify the inhibitors with minimal interference and matrixeffects.4.3 This test method has also been used successfully todetermine the inhibitor concentrations in other insulatingliquids such as esters and high-temperature hydrocarbons.5.Apparatus5.1 Gas Chromatograph,equipped with oven temperaturecontrol constant to 1 C and with heated injector port.5.1.1 Means to Record the Chromatogram,such as a penrecorder or a digital integrator to determine peak areas,isrecommended.An automated sample injector may be used.5.2 Flame Ionization Detector,with appropriate hydrogen/air gas flows,is preferred over a thermal conductivity detectorto provide maximum sensitivity.5.3 Column,a suitable stainless steel or glass columnpacked with a nonpolar silicone on an appropriate support orequivalent capillary column.1This test method is under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquids and Gases and is the direct responsibility of Subcom-mittee D27.03 on Analytical Tests.Current edition approved Dec.1,2019.Published December 2019.Originallyapproved in 1988 as D4768 88.Last previous edition approved in 2011 asD4768 11.DOI:10.1520/D4768-11R19.2For 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.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.1NOTE1A 3%OV-13on 100/120 Mesh Supelcoport,41.83 m(6 ft)long,3.2 mm(0.125 in.)in outside diameter has been used successfully.A SPB-1430 m by 0.53 mm 1m film column has also been usedsuccessfully.5.3.1 Condition columns in accordance with manufacturersrecommendations.Disconnect columns from detector prior toconditioning and reconnect after conditioning.5.4 Precision Syringe,glass,10.0 L.5.5 Volumetric Glassware,appropriate for making dilutions.5.6 Pipets