ASTM D3237-22

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D3237 − 17 D3237 − 22
Standard Test Method for
Lead in Gasoline by Atomic Absorption Spectroscopy
This standard is issued under the fixed designation D3237; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript 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 the total lead content of gasoline within the concentration range of 0.010 g to
0.10 g of lead/U.S. gal (2.5 mg ⁄L to 25 mg/L). This test method compensates for variations in gasoline composition and is
independent of lead alkyl type.
1.2 The values given in grams per U.S. gallon are to be regarded as the standard in the United States. Note that in other countries,
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 responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. For specific hazard statements, see 6.67.6 and 6.87.8.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1193 Specification for Reagent Water
D1368 Test Method for Trace Concentrations of Lead in Primary Reference Fuels (Withdrawn 1994)
D2550 Method of Test for Water Separation Characteristics of Aviation Turbine Fuels (Withdrawn 1989)
D3116 Test Method for Trace Amounts of Lead in Gasoline (Withdrawn 1994)
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-
ment System Performance
D6792 Practice for Quality Management Systems in Petroleum Products, Liquid Fuels, and Lubricants Testing Laboratories
D7740 Practice for Optimization, Calibration, and Validation of Atomic Absorption Spectrometry for Metal Analysis of
Petroleum Products and Lubricants
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.03 on Elemental Analysis.
Current edition approved June 1, 2017Oct. 1, 2022. Published June 2017November 2022. Originally approved in 1973. Last previous edition approved in 20122017 as
D3237 – 12.D3237 – 17. DOI: 10.1520/D3237-17.10.1520/D3237-22.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
*A Summary of Changes section appears at the end of this standard
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D3237 − 22
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this test method, refer to Terminology D4175.
4. Summary of Test Method
4.1 The gasoline sample is diluted with methyl isobutyl ketone and the alkyl lead components are stabilized by reaction with
iodine and a quaternary ammonium salt. The lead content of the sample is determined by flame atomic absorption flame
spectrometry at 283.3 nm, using standards prepared from reagent grade lead chloride. By the use of this treatment, all alkyl lead
compounds give identical response.
4.2 Protocols for using atomic absorption spectrometry are given in Practice D7740.
5. Significance and Use
5.1 This test method is used to ensure compliance of trace lead as required by federal regulation for lead-free gasoline (40 CFR
part 80).
6. Apparatus
6.1 Atomic Absorption Spectrometer, capable of scale expansion and nebulizer adjustment, and equipped with a slot burner and
premix chamber for use with an air-acetylene flame.
6.2 Volumetric Flasks, 50 mL, 100 mL, 250 mL, and 1 L sizes.
6.3 Pipets, 2 mL, 5 mL, 10 mL, 20 mL, and 50 mL sizes.
6.4 Micropipet, 100 μL, Eppendorf type or equivalent.
7. Reagents
7.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available.
7.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by
Types II or III of Specification D1193.
7.3 Aliquat 336 (tricapryl methyl ammonium chloride).
7.4 Aliquat 336/MIBK Solution (10 % volume per volume)—Dissolve and dilute 100 mL (88.0 g) of Aliquat 336 with MIBK to
1 L.
7.5 Aliquat 336/MIBK Solution (1 % volume per volume)—Dissolve and dilute 10 mL (8.8 g) of Aliquat 336 with MIBK to 1 L.
7.6 Iodine Solution—Dissolve and dilute 3.0 g of iodine crystals with toluene to 100 mL. (Warning—Flammable. Vapor harmful.)
7.7 Lead Chloride (PbCl ).
Reagent Chemicals, American Chemical Society Specifications,ACS Reagent Chemicals, Specifications and Procedures for Reagents and Standard-Grade Reference
Materials, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for
Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC),
Rockville, MD.
D3237 − 22
7.8 Lead-Sterile Gasoline—Gasoline containing less than 0.005 g Pb/gal (1.32 mg Pb/L). (Warning—Extremely flammable.
Harmful if inhaled. Vapors may cause flash fire.)
NOTE 1—One way to confirm lead concentrations of less than 0.005 g Pb/gal (1.32 mg Pb/L) is to refer to Test Methods D1368 and 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 lead concentration of low lead
gasoline in lead-sterile gasoline.
7.9 Lead, Standard Solution (5.0 g Pb/gal (1.32 g Pb/L))—Dissolve 0.4433 g of lead chloride (PbCl ) previously dried at 105 °C
for 3 h in about 200 mL of 10 % Aliquat 336/MIBK solution in a 250 mL volumetric flask. Dilute to the mark with the 10 % Aliquat
solution, mix, and store in a brown bottle having a polyethylene-lined cap. This solution contains 1321 μg Pb/mL, which is
equivalent to 5.0 g Pb ⁄gal.
7.10 Lead, Standard Solution (1.0 g Pb/gal (264 mg Pb/L))—By means of a pipet, accurately transfer 50.0 mL of the 5.0 g Pb ⁄gal
(1.32 g Pb/L) solution to a 250 mL volumetric flask, dilute to volume with 1 % Aliquat/MIBK solution. Store in a brown bottle
having a polyethylene-lined cap.
7.11 Lead, Standard Solutions (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
means of pipets 2.0 mL, 5.0 mL, and 10.0 mL of the 1.0 g Pb/gal (264 mg Pb/L) solution to 100 mL volumetric flasks; add 5.0 mL
of 1 % Aliquat 336 solution to each flask; dilute to the mark with MIBK. Mix well and store in bottles having polyethylene-lined
caps.
7.12 Methyl Isobutyl Ketone (MIBK), (4-methyl-2-pentanone).
7.13 Quality Control (QC) Samples, preferably are portions of one or more liquid petroleum materials that are
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