1、Designation: D3237 12Standard 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 Department of Defense.1. Scope*1.1 This test method covers the determination of the tot
3、allead content of gasoline within the concentration range of0.010 to 0.10 g of lead/U.S. gal (2.5 to 25 mg/L). This testmethod 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 standard in th
4、e 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 and determin
5、e the applica-bility of regulatory limitations prior to use. For specific hazardstatements, see 6.6 and 6.8.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1368 Test Method for Trace Concentrations of Lead inPrimary Reference Fuels (Withdrawn 1994)3D2550 Method of Te
6、st for Water Separation Characteristicsof Aviation Turbine Fuels (Withdrawn 1989)3D3116 Test Method for Trace Amounts of Lead in Gasoline(Withdrawn 1994)3D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD6299 Practice for Applying Statistical Quality Assuranceand Control Charting
7、 Techniques to Evaluate AnalyticalMeasurement System PerformanceD6792 Practice for Quality System in Petroleum Productsand Lubricants Testing LaboratoriesD7740 Practice for Optimization, Calibration, and Valida-tion of Atomic Absorption Spectrometry for Metal Analy-sis of Petroleum Products and Lubr
8、icants3. Summary of Test Method3.1 The gasoline sample is diluted with methyl isobutylketone and the alkyl lead components are stabilized by reactionwith iodine and a quaternary ammonium salt. The lead contentof the sample is determined by atomic absorption flamespectrometry at 283.3 nm, using stand
9、ards prepared fromreagent grade lead chloride. By the use of this treatment, allalkyl lead compounds give identical response.3.2 Protocols for using atomic absorption spectrometry aregiven in Practice D7740.4. Significance and Use4.1 This test method is used to ensure compliance of tracelead as requ
10、ired by federal regulation for lead-free gasoline (40CFR part 80).5. Apparatus5.1 Atomic Absorption Spectrometer, capable of scale ex-pansion and nebulizer adjustment, 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,
11、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.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.Cu
12、rrent edition approved June 1, 2012. Published August 2012. Originallyapproved in 1973. Last previous edition approved in 2006 as D3237 061. DOI:10.1520/D323712.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book o
13、f ASTMStandards volume 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
14、, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American
15、Chemical Society,where such specifications are available.46.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood 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
16、 (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 per volume)Dissolve and dilute 10 mL (8.8 g) of Aliquat 336 with MIBKto1L.6.6 Iodine SolutionDissolve and dilute 3.0 g of iodinecrystals with toluene to 100 mL. (Warni
17、ngFlammable.Vapor harmful.)6.7 Lead Chloride (PbCl2).6.8 Lead-Sterile GasolineGasoline containing less than0.005 g Pb/gal (1.32 mg Pb/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
18、/L) is to refer to Test Methods D1368 and D3116.Aprocedure for the purification of gas turbine fuel appears in Appendix X4of Test Method 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)Dissol
19、ve 0.4433 g of lead chloride (PbCl2) previously dried at105C for 3 h in about 200 mL of 10 % Aliquat 336/MIBKsolution in a 250-mL volumetric flask. Dilute to the mark withthe 10 % Aliquat solution, mix, and store in a brown bottlehaving a polyethylene-lined cap. This solution contains 1321g Pb/mL, w
20、hich 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 50.0 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 polyethy
21、lene-lined cap.6.11 Lead, Standard Solutions (0.02, 0.05, and 0.10 g Pb/gal(5.3, 13.2, and 26.4 mg Pb/L)Transfer accurately by meansof pipets 2.0, 5.0, and 10.0 mL of the 1.0-g Pb/gal (264 mgPb/L) solution to 100-mL volumetric flasks; add 5.0 mL of 1 %Aliquat 336 solution to each flask; dilute to th
22、e mark withMIBK. Mix well and store in bottles having polyethylene-linedcaps.6.12 Methyl Isobutyl Ketone (MIBK), (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. Th
23、ese QC samplescan be used to check the validity of the testing process asdescribed in Section 11.7. Sampling7.1 Take samples of gasoline in compliance with the in-structions in Practice D4057.7.2 Collect sample in a metal container that can be sealedagainst leakage and store under temperature-consis
24、tent condi-tions prior to analysis.8. Calibration8.1 Preparation of Working StandardsPrepare three work-ing standards and a blank using the 0.02, 0.05, and 0.10-gPb/gal (5.3, 13.2, and 26.4 mg Pb/L) standard lead solutionsdescribed in 6.11.8.1.1 To each of four 50-mL volumetric flasks containing 30m
25、L of MIBK, add 5.0 mL of low lead standard solution and 5.0mL of lead-free gasoline. In the case of the blank, add only 5.0mL 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 %
26、 Aliquat 336 solution. Dilute tovolume with MIBK and mix well.8.2 Preparation of InstrumentOptimize 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 incol
27、or.8.2.1 Aspirate the 0.1-g Pb/gal (26.4 mg Pb/L) workingstandard and adjust the burner 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 checkth
28、e absorbances of the three working standards for linearity.9. Procedure9.1 To a 50-mL 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 s
29、olution andmix.9.1.3 Dilute to volume with MIBK and mix.9.2 Aspirate the samples and working 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-t
30、ions of the samples from the graph.10.2 If the AAS instrument has built-in computer software,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
31、 American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D3237 12211. Quality Control11.1 Confirm the performance of the instrument or th
32、e testprocedure by analyzing a quality control (QC) sample (see6.13).11.1.1 When QC/Quality 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
33、facility, Appendix X1 can be used as the QC/QAsystem.NOTE 2Further guidance on QA/QC may 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 diffe
34、rence between two testresults, obtained by the same operator with the same apparatusunder 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
35、mg/L)12.1.2 ReproducibilityThe difference between two singleand independent results obtained 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:
36、0.01 g/U.S gal (2.6 mg/L)12.2 BiasThe bias for this test method was determined bytwo individual 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
37、.050, 0.051SRM2714 0.075 0.077, 0.079The values obtained are within the repeatability 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
38、 the testprocedure by analyzing quality control (QC) sample(s).X1.2 Prior to monitoring 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 statis
39、tically equivalent techniques to ascertain the statis-tical control status of the total 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
40、 testing is dependent on thecriticality of the quality being measured, the demonstratedstability 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 rout
41、inely analyzed. However,when it is demonstrated that the testing is under statisticalcontrol, 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 recommende
42、d that, if possible, the type of QCsample that is regularly tested be representative of 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 Footno
43、tes 6 and 7 for further guidance on QC andControl Charting techniques.5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D02-1376.6ASTM MNL 7, Manual on Presentation of Data Control Chart Analysis, 6thEd., Section 3, ASTM Internati
44、onal, W. Conshohocken, PA.7In the absence of explicit requirements given in the test method, this clauseprovides guidance on QC testing frequency.D3237 123SUMMARY OF CHANGESSubcommittee D02.03 has identified the location of selected changes to this standard since the last issue(D3237 061) that may i
45、mpact the use of this standard.(1) Added 3.2, 10.2, and Note 2.(2) Added Practices D6792 and D7740 to Referenced Docu-ments and standard text.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of thi
46、s standard are expressly advised that determination of the validity of 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 yea
47、rs 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 commit
48、tee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1942
49、8-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D3237 124
