1、Designation: D 3237 06e1An American National StandardStandard Test Method forLead in Gasoline by Atomic Absorption Spectroscopy1This standard is issued under the fixed designation D 3237; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.e1NOTECorrected footnote refere
3、nces in Paragraph X1.6 editorially in April 2007.1. Scope*1.1 This test method covers the determination of the totallead 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 in
4、dependent of lead alkyl type.1.2 The values given in grams per U.S. gallon are to beregarded as the standard 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
5、 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. For specific hazardstatements, see 6.6 and 6.8.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent Wa
6、terD 1368 Test Method for Trace Concentrations of Lead inPrimary Reference FuelsD 2550 Test Method for Water Separation Characteristics ofAviation Turbine Fuels3D3116 Test Method for Trace Amounts of Lead in Gaso-line3D 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 6299 Pract
7、ice for Applying Statistical Quality AssuranceTechniques to Evaluate Analytical Measurement SystemPerformance3. 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
8、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.4. Significance and Use4.1 This test method is used to ensure compliance
9、 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 adjustment, and equipped with a slotburner and premix chamber for use with an air-acetylene flame.5.2 Volumetric Flasks, 50
10、-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 chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to
11、 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 understood to mean reagent water as definedby Types II or III of Specification D 1193.6.3
12、Aliquat 336 (tricapryl methyl ammonium chloride).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 Dec. 1, 2006. Published January 2007. Originall
13、yapproved in 1973. Last previous edition approved in 2002 as D 323702.2For 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
14、 website.3Withdrawn.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., Poole, Dorset, U.K., and the Unit
15、ed States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.4 Aliquat 336/
16、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 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 1
17、00 mL. (WarningFlammable.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/ga
18、l (1.32 mg Pb/L) is to refer to Test Methods D 1368 and D3116.Aprocedure for the purification of gas turbine fuel appears in Appendix X4of Test Method D 2550 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 (1.3
19、2 g Pb/L)Dissolve 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
20、 1321g 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 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 ha
21、ving a polyethylene-lined cap.6.11 Lead, Standard Solutions (0.02, 0.05, and 0.10 gPb/gal (5.3, 13.2, and 26.4 mg Pb/L)Transfer accurately bymeans of pipets 2.0, 5.0, and 10.0 mL of the 1.0-g Pb/gal (264mg Pb/L) solution to 100-mL volumetric flasks; add 5.0 mL of1 % Aliquat 336 solution to each flas
22、k; dilute to the 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
23、of interest. These 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 D 4057.7.2 Collect sample in a metal container that can be sealedagainst leakage and store under te
24、mperature-consistent condi-tions prior to analysis.8. Calibration8.1 Preparation of Working StandardsPrepare threeworking 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
25、containing 30mL 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 A
26、dd 5 mL of 1 % 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 li
27、ght blue incolor.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 instrume
28、nt and checkthe 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 % Aliq
29、uat 336/MIBK solution 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 t
30、he concentra-tions of the samples from the graph.11. 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/Quality Assurance (QA) protocols arealready established in the testing facility, these may be us
31、edwhen 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.12. Precision and Bias12.1 PrecisionThe precision of this test method as ob-tained by statistical examination of interlaborator
32、y test resultsis as follows:12.1.1 RepeatabilityThe difference between two test re-sults, 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 follo
33、wing values only in one casein twenty:0.005 g/U.S gal (1.3 mg/L)D323706e1212.1.2 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 t
34、he 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 individual laboratories analyzing standard reference mate-rials.SampleCertified Pb, g/U.S. gal. Observed Results, g/U.S. gal.Laboratory 1 Laborato
35、ry 2SRM2712 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 of the testmethod and indicate no bias.513. Keywords13.1 atomic absorption; gasoline; lead; lead-freeAPPENDIX(Nonmandatory Information)X1. QUAL
36、ITY CONTROL MONITORINGX1.1 Confirm the performance of the instrument or 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 D 6299).
37、6X1.3 Record the QC results and analyze by control chartsor other statistically equivalent techniques to ascertain thestatistical control status of the total testing process (see PracticeD 6299).6,7Investigate any out-of-control data for rootcause(s). The results of this investigation may, but not n
38、eces-sarily, result in instrument re-calibration.X1.4 The frequency of QC 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.
39、The QC frequency should be increased ifa large number of samples are routinely 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 pr
40、ecision to ensure data quality (seePractice D 6299).6X1.5 It is recommended 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 behomoge
41、neous and stable under the anticipated storage condi-tions.X1.6 See Footnotes 6 and 7 for further guidance on QC andControl Charting techniques.SUMMARY OF CHANGESSubcommittee D02.03 has identified the location of selected changes to this standard since the last issue(D 323702) that may impact the us
42、e of this standard.(1) Updated Note 1.5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D021376.6ASTM MNL 7, Manual on Presentation of Data Control Chart Analysis, 6thEd., Section 3, ASTM International, W. Conshohocken, PA.7In th
43、e absence of explicit requirements given in the test method, this clauseprovides guidance on QC testing frequency.D323706e13ASTM 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 exp
44、ressly 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 years andif not revis
45、ed, 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, which you may
46、 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 19428-2959,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).D323706e14
