ASTM D6129-97(2021)

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.
Designation: D6129 − 97 (Reapproved 2021)
Standard Test Method for
Silicon in Engine Coolant Concentrates by Atomic
Absorption Spectroscopy
This standard is issued under the fixed designation D6129; 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.
1. Scope 3. Summary of Test Method
3.1 The sample is dissolved in water and the silicon content
1.1 This test method covers the determination of silicon in
the range from 200 ppm to 500 ppm in engine coolant is determined from a standard curve established at the time the
sample is run. An atomic absorption spectrometer with a
concentrates by atomic absorption. This method is as accurate
and precise as photometric methods, while requiring consider- nitrous oxide-acetylene flame is used.
ably less operator time and avoiding problems with reagent
4. Apparatus
instability.
1.1.1 Coolants with silicon content outside of this range
4.1 Atomic Absorption Spectrometer, with nitrous oxide-
may be analyzed by this method by suitably adjusting the
acetylene flame.
sample size. Care should be taken to ensure that the glycol
4.2 Hollow-Cathode Lamp, for silicon.
content of the working standards corresponds to that of the
sample solution being analyzed.
5. Reagents
1.2 The values stated in SI units are to be regarded as
5.1 Reagent grade chemicals shall be used in all tests.
standard. No other units of measurement are included in this
5.2 References to water shall be understood to mean dis-
standard.
tilled water or water of equal quality.
1.3 This standard does not purport to address all of the
5.3 Standard Silicon Solution, 1000 mg/L (see Note 1).
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5.4 Ethylene Glycol (propylene glycol should be used when
priate safety, health, and environmental practices and deter-
analyzing PG-based coolants).
mine the applicability of regulatory limitations prior to use.
5.5 Sodium Hydroxide, 5 % in water (see Note 1). When
1.4 This international standard was developed in accor-
preparing from solid sodium hydroxide avoid prolonged expo-
dance with internationally recognized principles on standard-
sure to the atmosphere. DO NOT STORE IN GLASS.
ization established in the Decision on Principles for the
5.6 Working standards: 0 mg⁄L, 20 mg⁄L, 40 mg⁄L, and
Development of International Standards, Guides and Recom-
60 mg⁄L silicon.
mendations issued by the World Trade Organization Technical
5.6.1 Prepare these solutions by pipeting 2.0 mL, 4.0 mL,
Barriers to Trade (TBT) Committee.
and 6.0 mL of the 1000 mg/L standard silicon solution into
separate 100 mL volumetric flasks. Add 10.0 mL of ethylene
2. Referenced Documents
glycol and 2.0 mL of 5 % sodium hydroxide solution to each
2.1 ASTM Standards:
flaskanddilutetovolumewithwater.Preparethezerostandard
D1176 Practice for Sampling and Preparing Aqueous Solu-
solution by adding 10.0 mL ethylene glycol and 2.0 mL 5 %
tions of Engine Coolants orAntirusts forTesting Purposes
sodium hydroxide solution to another 100 mLvolumetric flask
and diluting to volume with water.
NOTE 1—Standard silicon solutions and sodium hydroxide solutions are
This test method is under the jurisdiction ofASTM Committee D15 on Engine
available from most laboratory supply companies.
Coolants and Related Fluids and is the direct responsibility of Subcommittee
D15.04 on Chemical Properties.
Current edition approved Sept. 1, 2021. Published September 2021. Originally
approved in 1997. Last previous edition approved in 2015 as D6129 - 97(2015). Reagent Chemicals, American Chemical Society Specifications, American
DOI: 10.1520/D6129-97R21. Chemical Society, Washington, DC. For suggestions on the testing of reagents not
For referenced ASTM standards, visit the ASTM website, www.astm.org, or listed by the American Chemical Society, see Analar Standards for Laboratory
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