ASTM_D_7220_-_12.pdf

Designation:D722012Standard Test Method forSulfur in Automotive,Heating,and Jet Fuels byMonochromatic Energy Dispersive X-ray FluorescenceSpectrometry1This standard is issued under the fixed designation D7220;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 specifies an energy-dispersive X-rayfluorescence(EDXRF)method for the determination of totalsulfur in automotive,No.2 heating,and jet fuels with aconcentration range of 3 to 942 mg/kg.1.1.1 The pooled limit of quantitation of this test method asobtained by statistical analysis of inter laboratory test results is3 mg/kg sulfur.1.1.2 This test method is applicable to gasoline,oxygenenriched gasoline(RFG),diesel,diesel/biodiesel blends con-taining up to twenty volume percent biodiesel,kerosene,jetfuel,jet fuel/biodiesel blends containing up to five volumepercent biodiesel and No.2 home heating oil.1.2 Afundamental assumption in this test method is that thestandard and sample matrix is well matched.Matrix mismatchcan be caused by C/H ratio differences between samples andstandards or by the presence of other heteroatoms.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3.1 The preferred concentration units are mg/kg sulfur.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.2.Referenced Documents2.1 ASTM Standards:2D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6300 Practice for Determination of Precision and BiasData for Use in Test Methods for Petroleum Products andLubricantsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications3.Terminology3.1 Definitions:3.1.1 monochromatic X-radiation,nan incident X-raybeam on a sample having a selected photon energy with anarrow energy bandwidth of 65%relative to the selectedenergy.3.1.1.1 DiscussionMonochromatic X-ray radiation inEDXRF instrumentation can be obtained by using Bragg optics(at an angle of =45 6 5,in the low energy range).Braggoptics(monochromators)create very intense mono-energeticradiation.A combination of a selected X-ray tube(typically aPd or Ag anode)with a highly ordered pyrolytic graphite(HOPG)Bragg optic can be used to create monochromaticradiation of the characteristic radiation of the anode material ofthe X-ray tube.The use of such radiation for sample excitationresults in increased sensitivity for the determination of sulfur inpetroleum products.3.2 Abbreviations:3.2.1 DBSactual mass of Di-n-butyl sulfide,g3.2.2 Kcpskilo-counts per second.3.2.3 EDXRFEnergy dispersive X-ray spectrometry3.2.4 PTFEPolytetrafluorethylene3.2.5 SDBSmass%of sulfur in Di-n-butyl sulfide,typi-cally 21.91%3.2.6 SStdmg/kg sulfur in the calibration standard3.2.7 SStockmg/kg of sulfur in the stock standard3.2.8 STKactual mass of stock standard,g1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.03 on Elemental Analysis.Current edition approved Jan.15,2012.Published March 2012.Originallyapproved in 2006.Last previous edition approved in 2006 as D722006.DOI:10.1520/D7220-12.2For 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 States1 4.Summary of Test Method4.1 The sample is placed in the monochromatic X-ray beam,and the peak area of the sulfur Ka line at 2.307 keV ismeasured.The background spectrum,measured with a sulfurfree white oil or other matrix matching blank sample(see 8.4)is adapted to the measured spectrum using adjustment regionsfollowing the instrument manufacturers instructions and thensubtracted from the measured spectrum.The resultant netcounting rate is then compared to a previously preparedcalibration curve or equation to obtain the concentration ofsulfur in mg/kg.(WarningExposure to excessive quantitiesof X-radiation is injurious to health.The operator needs to takeappropriate actions to avoid exposing any part of their body,not only to primary X-rays,but also to secondary or scatteredradi