ASTM_D_6732_-_04_2020.pdf

Designation:D673204(Reapproved 2020)Standard Test Method forDetermination of Copper in Jet Fuels by Graphite FurnaceAtomic Absorption Spectrometry1This standard is issued under the fixed designation D6732;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 of copper injet fuels in the range of 5 g kg to 100 g kg using graphitefurnace atomic absorption spectrometry.Copper contentsabove 100 gkg may be determined by sample dilution withkerosine to bring the copper level into the aforementionedmethod range.When sample dilution is used,the precisionstatements do not apply.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 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.1.4 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:2D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4306 Practice for Aviation Fuel Sample Containers forTests Affected by Trace ContaminationD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System Performance3.Terminology3.1 Definitions:3.1.1 radiant power,P,nthe rate at which energy istransported in a beam of radiant energy.3.1.2 transmittance,T,nthe ratio of the radiant powertransmitted by a material to the radiant power incident upon it.3.2 Definitions of Terms Specific to This Standard:3.2.1 absorbance,A,nthe logarithm to the base 10 of theratio of the reciprocal of the transmittance,T:A 5 log101/T!5 2log10T(1)3.2.2 integrated absorbance,Ai,nthe integrated area un-der the absorbance peak generated by the atomic absorptionspectrometer.4.Summary of Test Method4.1 The graphite furnace is aligned in the light path of theatomic absorption spectrometer equipped with backgroundcorrection.An aliquot(typically 10 L)of the sample ispipetted onto a platform in the furnace.The furnace is heatedto low temperature to dry the sample completely withoutspattering.The furnace is then heated to a moderate tempera-ture to eliminate excess sample matrix.The furnace is furtherheated very rapidly to a temperature high enough to volatilizethe analyte of interest.It is during this step that the amount oflight absorbed by the copper atoms is measured by thespectrometer.4.2 The light absorbed is measured over a specified period.The integrated absorbance Aiproduced by the copper in thesamples is compared to a calibration curve constructed frommeasured Aivalues for organo-metallic standards.5.Significance and Use5.1 At high temperatures aviation turbine fuels can oxidizeand produce insoluble deposits that are detrimental to aircraftpropulsion systems.Very low copper concentrations(in excessof 50 g kg)can significantly accelerate this thermal instabilityof aviation turbine fuel.Naval shipboard aviation fuel deliverysystems contain copper-nickel piping,which can increasecopper levels in the fuel.This test method may be used forquality checks of copper levels in aviation fuel samples takenon shipboard,in refineries,and at fuel storage depots.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.03 on Elemental Analysis.Current edition approved May 1,2020.Published June 2020.Originallyapproved in 2001.Last previous edition approved in 2015 as D6732 04(2015).DOI:10.1520/D6732-04R20.2For 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.6.Interferences6.1 Interferences most commonly occur due to light that isabsorbed by species o