ASTM_D_7212_-_13.pdf

Designation:D721213Standard Test Method forLow Sulfur in Automotive Fuels by Energy-Dispersive X-rayFluorescence Spectrometry Using a Low-BackgroundProportional Counter1This standard is issued under the fixed designation D7212;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.Scope*1.1 This test method specifies an energy-dispersive X-rayfluorescence(EDXRF)method for the determination of thetotal sulfur content of automotive fuels with a concentrationrange from 7 mg/kg to 50 mg/kg.1.1.1 The pooled limit of quantitation of this test method asobtained by statistical analysis of interlaboratory test results is7 mg/kg sulfur.1.2 The values stated in SI units are to be regarded as thestandard.The preferred concentration units are mg/kg sulfur.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D4045 Test Method for Sulfur in Petroleum Products byHydrogenolysis and Rateometric ColorimetryD4057 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 andLubricantsD6792 Practice for Quality System in Petroleum Productsand Lubricants Testing LaboratoriesD7343 Practice for Optimization,Sample Handling,Calibration,and Validation of X-ray Fluorescence Spec-trometry Methods for Elemental Analysis of PetroleumProducts and LubricantsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 low background proportional counter,nan X-rayproportional counter that can suppress the noise generatedwhen incident X rays are absorbed near the wall with resultingincomplete charge collection.3.1.1.1 DiscussionAn electrode shield close to the walldetects incomplete charge collection and associated electronicdetection circuitry rejects those events.In comparison toconventional proportional counters,this gives lower spectralbackground and a lower limit of detection.4.Summary of Test Method4.1 The sample is placed in the beam emitted from an X-raysource with titanium target and primary filtration so thatexcitation is by essentially monochromatic radiation of4.51 keV and virtually no background at 2.3 keV.A lowbackground proportional counter measures the intensity of thefluorescent sulfur K series intensity and argon K series inten-sity(from residual air)and the accumulated counts are com-pared with counts from previously prepared calibration stan-dards to obtain the sulfur concentration in mg/kg.If chlorine isexpected to be present in some samples then other regions ofthe spectrum must be measured to provide compensation forspectral overlap.One group of calibration standards is requiredto span the concentration range from 0 to 150 mg/kg sulfur.NOTE1Operation of analyzers using X-ray tubes is to be conductedin accordance with the manufacturers safety instructions and federal,state,and local regulations governing the use of ionizing radiation.4.2 Practice D7343 should be consulted regarding standardoperating protocols in XRF analysis.1This 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 June 15,2013.Published August 2013.Originallyapproved in 2006.Last previous edition approved in 2007 as D7212 07.DOI:10.1520/D7212-13.2For 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.*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.United States1 5.Significance and Use5.1 This test method determines total sulfur in automotivefuels with a typical analysis time around 10 min per sample.5.2 The quality of automotive fuel is related to the amountof sulfur present.Knowledge of sulfur level is necessary forprocessing purposes.5.3 Sulfur level in automotive fuels affects performancecharacteristics and air quality.Federal,state,and local agenciesregulate the level of sulfur in fuel delivered at