1、Designation: D3237 17Standard Test Method forLead in Gasoline by Atomic Absorption Spectroscopy1This standard is issued under the fixed designation D3237; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、 number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This test method covers the determination of th
3、e totallead content of gasoline within the concentration range of0.010 g to 0.10 g of lead/U.S. gal (2.5 mg L to 25 mg/L). Thistest method compensates for variations in gasoline compositionand is independent of lead alkyl type.1.2 The values given in grams per U.S. gallon are to beregarded as the st
4、andard in the United States. Note that in othercountries, other units can be preferred.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
5、and determine the applica-bility of regulatory limitations prior to use. For specific hazardstatements, see 6.6 and 6.8.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelop
6、ment 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 WaterD1368 Test Method for Trace Concentrations of Lead inPrimary Reference Fuels
7、(Withdrawn 1994)3D2550 Method of Test for Water Separation Characteristicsof Aviation Turbine Fuels (Withdrawn 1989)3D3116 Test Method for Trace Amounts of Lead in Gasoline(Withdrawn 1994)3D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of P
8、etroleum andPetroleum ProductsD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6792 Practice for Quality Management Systems in Petro-leum Products, Liquid Fuels, and Lubricants TestingLaboratoriesD7740 Pract
9、ice for Optimization, Calibration, and Valida-tion of Atomic Absorption Spectrometry for Metal Analy-sis of Petroleum Products and Lubricants3. Summary of Test Method3.1 The gasoline sample is diluted with methyl isobutylketone and the alkyl lead components are stabilized by reactionwith iodine and
10、a quaternary ammonium salt. The lead contentof the sample is determined by atomic absorption flamespectrometry at 283.3 nm, using standards prepared fromreagent grade lead chloride. By the use of this treatment, allalkyl lead compounds give identical response.3.2 Protocols for using atomic absorptio
11、n spectrometry aregiven in Practice D7740.4. Significance and Use4.1 This test method is used to ensure compliance of tracelead as required by federal regulation for lead-free gasoline (40CFR part 80).5. Apparatus5.1 Atomic Absorption Spectrometer, capable of scale ex-pansion and nebulizer adjustmen
12、t, and equipped with a slotburner and premix chamber for use with an air-acetylene flame.5.2 Volumetric Flasks, 50 mL, 100 mL, 250 mL, and 1 Lsizes.5.3 Pipets, 2 mL, 5 mL, 10 mL, 20 mL, and 50 mL sizes.5.4 Micropipet, 100 L, Eppendorf type or equivalent.6. Reagents6.1 Purity of ReagentsReagent grade
13、 chemicals shall beused in all tests. Unless otherwise indicated, it is intended that1This 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 appro
14、ved June 1, 2017. Published June 2017. Originallyapproved in 1973. Last previous edition approved in 2012 as D3237 12. DOI:10.1520/D3237-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volum
15、e information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West C
16、onshohocken, 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
17、 Organization Technical Barriers to Trade (TBT) Committee.1all reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.46.2 Purity of WaterUnless otherwise indicated, referencesto water shall be un
18、derstood to mean reagent water as definedby Types II or III of Specification D1193.6.3 Aliquat 336 (tricapryl methyl ammonium chloride).6.4 Aliquat 336/MIBK Solution (10 % volume pervolume)Dissolve and dilute 100 mL (88.0 g) of Aliquat 336with MIBK to 1 L.6.5 Aliquat 336/MIBK Solution (1 % volume pe
19、r volume)Dissolve and dilute 10 mL(8.8 g) ofAliquat 336 with MIBK to1L.6.6 Iodine SolutionDissolve and dilute 3.0 g of iodinecrystals with toluene to 100 mL. (WarningFlammable. Va-por harmful.)6.7 Lead Chloride (PbCl2).6.8 Lead-Sterile GasolineGasoline containing less than0.005 g Pb/gal (1.32 mg Pb/
20、L). (WarningExtremely flam-mable. Harmful if inhaled. Vapors may cause flash fire.)NOTE 1One way to confirm lead concentrations of less than 0.005 gPb/gal (1.32 mg Pb/L) is to refer to Test Methods D1368 and D3116.Aprocedure for the purification of gas turbine fuel appears in Appendix X4of Test Meth
21、od D2550 and can be used to decrease the lead concentrationof low lead gasoline in lead-sterile gasoline.6.9 Lead, Standard Solution (5.0 g Pb/gal (1.32 g Pb/L)Dissolve 0.4433 g of lead chloride (PbCl2) previously dried at105 C for 3 h in about 200 mL of 10 % Aliquat 336/MIBKsolution in a 250 mL vol
22、umetric flask. Dilute to the mark withthe 10 % Aliquat solution, mix, and store in a brown bottlehaving a polyethylene-lined cap. This solution contains1321 g Pb/mL, which is equivalent to 5.0 g Pb gal.6.10 Lead, Standard Solution (1.0 g Pb/gal (264 mg Pb/L)By means of a pipet, accurately transfer 5
23、0.0 mL of the5.0 g Pb gal (1.32 g Pb/L) solution to a 250 mL volumetricflask, dilute to volume with 1 % Aliquat/MIBK solution. Storein a brown bottle having a polyethylene-lined cap.6.11 Lead, Standard Solutions (0.02 g, 0.05 g, and 0.10 gPb/gal (5. 3 mg, 13.2 mg, and 26.4 mg Pb/L)Transfer accu-rate
24、ly by means of pipets 2.0 mL, 5.0 mL, and 10.0 mL of the1.0 g Pb/gal (264 mg Pb/L) solution to 100 mL volumetricflasks; add 5.0 mL of 1 % Aliquat 336 solution to each flask;dilute to the mark with MIBK. Mix well and store in bottleshaving polyethylene-lined caps.6.12 Methyl Isobutyl Ketone (MIBK), (
25、4-methyl-2-pentanone).6.13 Quality Control (QC) Samples, preferably are portionsof one or more liquid petroleum materials that are stable andrepresentative of the samples of interest. These QC samplescan be used to check the validity of the testing process asdescribed in Section 11.7. Sampling7.1 Ta
26、ke samples of gasoline in compliance with the in-structions in Practice D4057 or Practice D4177.7.2 Collect sample in a metal container that can be sealedagainst leakage and store under temperature-consistent condi-tions prior to analysis.8. Calibration8.1 Preparation of Working StandardsPrepare thr
27、ee work-ing standards and a blank using the 0.02 g, 0.05 g, and 0.10 gPb/gal (5.3 mg, 13.2 mg, and 26.4 mg Pb/L) standard leadsolutions described in 6.11.8.1.1 To each of four 50 mL volumetric flasks containing30 mL of MIBK, add 5.0 mL of low lead standard solution and5.0 mL of lead-free gasoline. I
28、n the case of the blank, add only5.0 mL of lead-free gasoline.8.1.2 Add immediately 0.1 mL of iodine/toluene solution bymeans of the 100-L Eppendorf pipet. Mix well and allow toreact for 1 min.8.1.3 Add 5 mL of 1 % Aliquat 336 solution. Dilute tovolume with MIBK and mix well.8.2 Preparation of Instr
29、umentOptimize the atomic ab-sorption equipment for lead at 283.3 nm. Using the reagentblank, adjust the gas mixture and the sample aspiration rate toobtain an oxidizing flame which is fuel lean and light blue incolor.8.2.1 Aspirate the 0.1 g Pb/gal (26.4 mg Pb L) workingstandard and adjust the burne
30、r position to give maximumresponse. Some instruments require the use of scale expansionto produce an absorbance reading of 0.150 to 0.170 for thisstandard.8.2.2 Aspirate the blank to zero the instrument and checkthe absorbances of the three working standards for linearity.9. Procedure9.1 To a 50 mL
31、volumetric flask containing 30 mL MIBK,add 5.0 mL of gasoline sample and mix.9.1.1 Add 0.10 mL (100 L) of iodine/toluene solution andallow the mixture to react about 1 min.9.1.2 Add 5.0 mL of 1 % Aliquat 336/MIBK solution andmix.9.1.3 Dilute to volume with MIBK and mix.9.2 Aspirate the samples and w
32、orking standards and recordthe absorbance values with frequent checks of the zero.10. Calculation10.1 Plot the absorbance values versus the concentrationrepresented by the working standards and read the concentra-tions of the samples from the graph.10.2 If the AAS instrument has built-in computer so
33、ftware,it can be used to do the above calculations.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Po
34、ole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D3237 17211. Quality Control11.1 Confirm the performance of the instrument or the testprocedure by analyzing a quality control (QC) sample (see6.13).11.1.1 When QC/Qu
35、ality Assurance (QA) protocols arealready established in the testing facility, these may be usedwhen they confirm the reliability of the test result.11.1.2 When there is no QC/QA protocol established in thetesting facility, Appendix X1 can be used as the QC/QAsystem.NOTE 2Further guidance on QA/QC m
36、ay be found in Practice D6792.12. Precision and Bias12.1 PrecisionThe precision of this test method as ob-tained by statistical examination of interlaboratory test resultsis as follows:12.1.1 RepeatabilityThe difference between two testresults, obtained by the same operator with the same apparatusun
37、der constant operating conditions on identical test material,would in the long run, in the normal and correct operation ofthe test method, exceed the following values only in one casein twenty:0.005 g U.S gal (1.3 mg L)12.1.2 ReproducibilityThe difference between two singleand independent results ob
38、tained by different operators indifferent laboratories on identical test material would, in thelong run, in the normal and correct operation of the testmethod, exceed the following values only in one case intwenty:0.01 g U.S gal (2.6 mg L)12.2 BiasThe bias for this test method was determined bytwo i
39、ndividual laboratories analyzing standard reference mate-rials.Certified Pb, g/U.S. gal. Observed Results, g/U.S.galSample Laboratory 1 Laboratory2SRM2712 0.031 0.032, 0.033 0.034, 0.033SRM2713 0.052 0.051, 0.054 0.050, 0.051SRM2714 0.075 0.077, 0.079The values obtained are within the repeatability
40、of the testmethod and indicate no bias.513. Keywords13.1 atomic absorption; gasoline; lead; lead-freeAPPENDIX(Nonmandatory Information)X1. QUALITY CONTROL MONITORINGX1.1 Confirm the performance of the instrument or the testprocedure by analyzing quality control (QC) sample(s).X1.2 Prior to monitorin
41、g the measurement process, the userof the method needs to determine the average value and controllimits of the QC sample (see Practice D6299).6X1.3 Record the QC results and analyze by control charts orother statistically equivalent techniques to ascertain the statis-tical control status of the tota
42、l testing process (see PracticeD6299).6,7Investigate any out-of-control data for root cause(s).The results of this investigation may, but not necessarily, resultin instrument re-calibration.X1.4 The frequency of QC testing is dependent on thecriticality of the quality being measured, the demonstrate
43、dstability of the testing process, and customer requirements.Generally, a QC sample should be analyzed each testing daywith routine samples. The QC frequency should be increased ifa large number of samples are routinely analyzed. However,when it is demonstrated that the testing is under statisticalc
44、ontrol, the QC testing frequency may be reduced. The QCsample testing precision should be periodically checked againstthe ASTM test method precision to ensure data quality (seePractice D6299).6X1.5 It is recommended that, if possible, the type of QCsample that is regularly tested be representative o
45、f the materialroutinely analyzed. An ample supply of QC sample materialshould be available for the intended period of use, and must behomogeneous and stable under the anticipated storage condi-tions.X1.6 See Footnotes 6 and 7 for further guidance on QC andControl Charting techniques.5Supporting data
46、 have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D02-1376. ContactASTM CustomerService at serviceastm.org.6ASTM MNL 7, Manual on Presentation of Data Control Chart Analysis, 6thEd., Section 3, ASTM International, W. Conshohocken, PA.7In the abse
47、nce of explicit requirements given in the test method, this clauseprovides guidance on QC testing frequency.D3237 173SUMMARY OF CHANGESSubcommittee D02.03 has identified the location of selected changes to this standard since the last issue(D3237 12) that may impact the use of this standard. (Approv
48、ed June 1, 2017.)(1) Practice D4177 was added to subsections 2.1 and 7.1.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity o
49、f any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee
