1、Designation: D3237 12D3237 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 rev
2、ision. A 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 determinati
3、on of the total lead content of gasoline within the concentration range of0.0100.010 g to 0.10 g 0.10 g of lead/U.S. gal (2.5(2.5 mgL to 25 mg/L). This test method compensates for variations in gasolinecomposition and is independent of lead alkyl type.1.2 The values given in grams per U.S. gallon ar
4、e to be regarded 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 the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate sa
5、fety and health practices and determine the applicability of regulatorylimitations prior to use. For specific hazard statements, see 6.6 and 6.8.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Pri
6、nciples for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1368 Test Method for Trace Concentrations of Lead in P
7、rimary Reference Fuels (Withdrawn 1994)3D2550 Method of Test for Water Separation Characteristics of Aviation Turbine Fuels (Withdrawn 1989)3D3116 Test Method for Trace Amounts of Lead in Gasoline (Withdrawn 1994)3D4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD4177 Practice f
8、or Automatic Sampling of Petroleum and Petroleum ProductsD6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-ment System PerformanceD6792 Practice for Quality Management Systems in Petroleum Products, Liquid Fuels, and Lubricants T
9、esting LaboratoriesD7740 Practice for Optimization, Calibration, and Validation of Atomic Absorption Spectrometry for Metal Analysis ofPetroleum Products and Lubricants3. Summary of Test Method3.1 The gasoline sample is diluted with methyl isobutyl ketone and the alkyl lead components are stabilized
10、 by reaction withiodine and a quaternary ammonium salt. The lead content of the sample is determined by atomic absorption flame spectrometryat 283.3 nm, 283.3 nm, using standards prepared from reagent grade lead chloride. By the use of this treatment, all alkyl leadcompounds give identical response.
11、3.2 Protocols for using atomic absorption spectrometry are given in Practice D7740.4. Significance and Use4.1 This test method is used to ensure compliance of trace lead as required by federal regulation for lead-free gasoline (40 CFRpart 80).1 This test method is under the jurisdiction of ASTM Comm
12、ittee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.03 on Elemental Analysis.Current edition approved June 1, 2012June 1, 2017. Published August 2012June 2017. Originally approved in 1973. Last previous edition approved in 200620
13、12 asD3237D3237 12. 061. DOI: 10.1520/D323712.10.1520/D3237-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM websit
14、e.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible t
15、o adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright
16、 ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Apparatus5.1 Atomic Absorption Spectrometer, capable of scale expansion and nebulizer adjustment, and equipped with a slot burner andpremix chamber for use with an air-acetylene flame.5.2 Volu
17、metric Flasks, 50-mL, 100-mL, 250-mL, and 1-L50 mL, 100 mL, 250 mL, and 1 L sizes.5.3 Pipets, 2-mL, 5-mL, 10-mL, 20-mL, and 50-mL2 mL, 5 mL, 10 mL, 20 mL, and 50 mL sizes.5.4 Micropipet, 100-L,100 L, Eppendorf type or equivalent.6. Reagents6.1 Purity of ReagentsReagent grade chemicals shall be used
18、in all tests. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, wheresuch specifications are available.46.2 Purity of WaterUnless otherwise indicated, references to water shall be
19、understood to mean reagent water as defined byTypes II or III of Specification D1193.6.3 Aliquat 336 (tricapryl methyl ammonium chloride).6.4 Aliquat 336/MIBK Solution (10 % volume per volume)Dissolve and dilute 100 mL (88.0 g) 100 mL (88.0 g) of Aliquat336 with MIBK to 1 L.1 L.6.5 Aliquat 336/MIBK
20、Solution (1 % volume per volume)Dissolve and dilute 10 mL(8.8 g) 10 mL(8.8 g) ofAliquat 336 withMIBK to 1 L.1 L.6.6 Iodine SolutionDissolve and dilute 3.0 g 3.0 g of iodine crystals with toluene to 100 mL. 100 mL. (WarningFlammable. Vapor harmful.)6.7 Lead Chloride (PbCl2).6.8 Lead-Sterile GasolineG
21、asoline containing less than 0.005 g Pb/gal (1.32 mg 0.005 g Pb/gal (1.32 mg Pb/L). (WarningExtremely flammable. Harmful if inhaled. Vapors may cause flash fire.)NOTE 1One way to confirm lead concentrations of less than 0.005 g Pb/gal (1.32 mg 0.005 g Pb/gal (1.32 mg Pb/L) is to refer to Test Method
22、s D1368and D3116. A procedure for the purification of gas turbine fuel appears in Appendix X4 of Test Method D2550 and can be used to decrease the leadconcentration of low lead gasoline in lead-sterile gasoline.6.9 Lead, Standard Solution (5.0 g Pb/gal (1.32 g (5.0 g Pb/gal (1.32 g Pb/L)Dissolve 0.4
23、433 g 0.4433 g of lead chloride(PbCl2) previously dried at 105C105 C for 3 h 3 h in about 200 mL 200 mL of 10 % Aliquat 336/MIBK solution in a250-mL250 mL volumetric flask. Dilute to the mark with the 10 % Aliquat solution, mix, and store in a brown bottle having apolyethylene-lined cap. This soluti
24、on contains 1321 g 1321 g Pb/mL, which is equivalent to 5.0 g 5.0 g PbPb/gal.gal.6.10 Lead, Standard Solution (1.0 g Pb/gal (264 mg (1.0 g Pb/gal (264 mg Pb/L)By means of a pipet, accurately transfer 50.0mL 50.0 mL of the 5.0 g5.0 g Pb Pb/gal (1.32 g gal (1.32 g Pb/L) solution to a 250-mL250 mL volu
25、metric flask, dilute to volumewith 1 % Aliquat/MIBK solution. Store in a brown bottle having a polyethylene-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 (0.02 g, 0.05 g, and 0.10 g Pb/gal (5. 3 mg,13.2 mg, and 26.4 mg Pb/L)Transfer accurately by mean
26、s of pipets 2.0, 5.0, and 10.0 mL 2.0 mL, 5.0 mL, and 10.0 mL of the1.0-g1.0 g Pb/gal (264 mg (264 mg Pb/L) solution to 100-mL100 mL volumetric flasks; add 5.0 mL 5.0 mL of 1 % Aliquat 336solution to each flask; dilute to the mark with MIBK. Mix well and store in bottles having polyethylene-lined ca
27、ps.6.12 Methyl Isobutyl Ketone (MIBK), (4-methyl-2-pentanone).6.13 Quality Control (QC) Samples, preferably are portions of one or more liquid petroleum materials that are stable andrepresentative of the samples of interest. These QC samples can be used to check the validity of the testing process a
28、s describedin Section 11.7. Sampling7.1 Take samples of gasoline in compliance with the instructions in Practice D4057 or Practice D4177.7.2 Collect sample in a metal container that can be sealed against leakage and store under temperature-consistent conditionsprior to analysis.4 Reagent Chemicals,
29、American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFor
30、mulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D3237 1728. Calibration8.1 Preparation of Working StandardsPrepare three working standards and a blank using the 0.02, 0.05,0.02 g, 0.05 g, and0.10-g0.10 g Pb/gal (5.3, 13.2, and 26.4 mg (5.3 mg, 13.2 mg, and 26.4 mg Pb/L) standard le
31、ad solutions described in 6.11.8.1.1 To each of four 50-mL50 mL volumetric flasks containing 30 mL 30 mL of MIBK, add 5.0 mL 5.0 mL of low leadstandard solution and 5.0 mL 5.0 mL of lead-free gasoline. In the case of the blank, add only 5.0 mL 5.0 mL of lead-free gasoline.8.1.2 Add immediately 0.1 m
32、L 0.1 mL of iodine/toluene solution by means of the 100-L Eppendorf pipet. Mix well and allowto react for 1 min.1 min.8.1.3 Add 5 mL 5 mL of 1 % Aliquat 336 solution. Dilute to volume with MIBK and mix well.8.2 Preparation of InstrumentOptimize the atomic absorption equipment for lead at 283.3 nm. 2
33、83.3 nm. Using the reagentblank, adjust the gas mixture and the sample aspiration rate to obtain an oxidizing flame which is fuel lean and light blue in color.8.2.1 Aspirate the 0.1-g0.1 g Pb/gal (26.4 mg(26.4 mg Pb Pb/L) L) working standard and adjust the burner position to givemaximum response. So
34、me instruments require the use of scale expansion to produce an absorbance reading of 0.150 to 0.170 forthis standard.8.2.2 Aspirate the blank to zero the instrument and check the absorbances of the three working standards for linearity.9. Procedure9.1 To a 50-mL50 mL volumetric flask containing 30
35、mL 30 mL MIBK, add 5.0 mL 5.0 mL of gasoline sample and mix.9.1.1 Add 0.10 mL (100 L) 0.10 mL (100 L) of iodine/toluene solution and allow the mixture to react about 1 min.1 min.9.1.2 Add 5.0 mL 5.0 mL of 1 % Aliquat 336/MIBK solution and mix.9.1.3 Dilute to volume with MIBK and mix.9.2 Aspirate the
36、 samples and working standards and record the absorbance values with frequent checks of the zero.10. Calculation10.1 Plot the absorbance values versus the concentration represented by the working standards and read the concentrations ofthe samples from the graph.10.2 If the AAS instrument has built-
37、in computer software, it can be used to do the above calculations.11. Quality Control11.1 Confirm the performance of the instrument or the test procedure by analyzing a quality control (QC) sample (see 6.13).11.1.1 When QC/Quality Assurance (QA) protocols are already established in the testing facil
38、ity, these may be used when theyconfirm the reliability of the test result.11.1.2 When there is no QC/QA protocol established in the testing facility, Appendix X1 can be used as the QC/QA system.NOTE 2Further guidance on QA/QC may be found in Practice D6792.12. Precision and Bias12.1 PrecisionThe pr
39、ecision of this test method as obtained by statistical examination of interlaboratory test results is asfollows:12.1.1 RepeatabilityThe difference between two test results, obtained by the same operator with the same apparatus underconstant operating conditions on identical test material, would in t
40、he long run, in the normal and correct operation of the testmethod, exceed the following values only in one case in twenty:0.0050.005 g g/U.S U.S gal (1.3 (1.3 mgmg/L)L)12.1.2 ReproducibilityThe difference between two single and independent results obtained by different operators in differentlaborat
41、ories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed thefollowing values only in one case in twenty:0.010.01 g g/U.S U.S gal (2.6 (2.6 mgmg/L)L)12.2 BiasThe bias for this test method was determined by two individual laboratories anal
42、yzing standard reference materials.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 of the test method and indic
43、ate no bias.55 Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D02-1376. Contact ASTM CustomerService at serviceastm.org.D3237 17313. Keywords13.1 atomic absorption; gasoline; lead; lead-freeAPPENDIX(Nonmandatory Information)X1.
44、 QUALITY CONTROL MONITORINGX1.1 Confirm the performance of the instrument or the test procedure by analyzing quality control (QC) sample(s).X1.2 Prior to monitoring the measurement process, the user of the method needs to determine the average value and control limitsof the QC sample (see Practice D
45、6299).6X1.3 Record the QC results and analyze by control charts or other statistically equivalent techniques to ascertain the statisticalcontrol status of the total testing process (see Practice D6299).6,7 Investigate any out-of-control data for root cause(s). The resultsof this investigation may, b
46、ut not necessarily, result in instrument re-calibration.X1.4 The frequency of QC testing is dependent on the criticality of the quality being measured, the demonstrated stability of thetesting process, and customer requirements. Generally, a QC sample should be analyzed each testing day with routine
47、 samples. TheQC frequency should be increased if a large number of samples are routinely analyzed. However, when it is demonstrated that thetesting is under statistical control, the QC testing frequency may be reduced. The QC sample testing precision should beperiodically checked against the ASTM te
48、st method precision to ensure data quality (see Practice D6299).6X1.5 It is recommended that, if possible, the type of QC sample that is regularly tested be representative of the material routinelyanalyzed. An ample supply of QC sample material should be available for the intended period of use, and
49、 must be homogeneousand stable under the anticipated storage conditions.X1.6 See Footnotes 6 and 7 for further guidance on QC and Control Charting techniques.SUMMARY OF CHANGESSubcommittee D02.03 has identified the location of selected changes to this standard since the last issue(D3237 06 12)1) that may impact the use of this standard. (Approved June 1, 2017.)(1) AddedPractice 3.2D4177, 10.2, andwas added Note 2to subsections 2.1 and 7.1.(2) Added Practices D6792 and D7740 to Referenced Documents and standard text.ASTM Internationa
