ASTM D6129-97(2021)

Standard Test Method for Silicon in Engine Coolant Concentrates by Atomic Absorption Spectroscopy

ABSTRACT
This standard test method covers the determination of silicon in engine coolant concentrates by atomic absorption spectroscopy. Apparatus and reagents used for this test method include atomic absorption spectrometer, hollow-cathode lamp, reagent grade chemicals, standard silicon solution, ethylene glycol or propylene glycol, and sodium hydroxide. Silicon content shall be determined from an established standard curve and an atomic absorption spectrometer. A nitrous oxide-acetylene flame shall be used.
SCOPE
1.1 This test method covers the determination of silicon in the range from 200 ppm to 500 ppm in engine coolant concentrates by atomic absorption. This method is as accurate and precise as photometric methods, while requiring considerably less operator time and avoiding problems with reagent instability.  
1.1.1 Coolants with silicon content outside of this range may be analyzed by this method by suitably adjusting the sample size. Care should be taken to ensure that the glycol content of the working standards corresponds to that of the sample solution being analyzed.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
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.

General Information

• Status: Published
• Publication Date: 31-Aug-2021
• ICS: 71.100.45 - Refrigerants and antifreezes
• Technical Committee: D15 - Engine Coolants and Related Fluids
• Drafting Committee: D15.04 - Chemical Properties

Relations

• Refers: ASTM D1176-14(2019) - Standard Practice for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antirusts for Testing Purposes
• Effective Date: 01-Oct-2019
• Refers: ASTM D1176-14 - Standard Practice for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antirusts for Testing Purposes
• Effective Date: 01-Apr-2014
• Refers: ASTM D1176-98(2008) - Standard Practice for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antirusts for Testing Purposes
• Effective Date: 01-Apr-2008
• Refers: ASTM D1176-98(2002) - Standard Practice for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antirusts for Testing Purposes
• Effective Date: 10-Apr-1998
• Refers: ASTM D1176-98 - Standard Practice for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antirusts for Testing Purposes
• Effective Date: 10-Apr-1998

Overview

ASTM D6129-97(2021) is a widely recognized standard published by ASTM International, detailing the Standard Test Method for Silicon in Engine Coolant Concentrates by Atomic Absorption Spectroscopy. This method provides industry professionals with a reliable procedure for determining silicon concentrations, specifically within the 200 ppm to 500 ppm range, in engine coolant concentrates. By utilizing atomic absorption spectroscopy rather than traditional photometric techniques, this standard offers improved efficiency, significant time savings, and enhanced precision.

The determination of silicon is essential for quality control and product development in automotive and industrial cooling systems, helping manufacturers and laboratories maintain fluid performance and equipment longevity.

Key Topics

• Scope and Range: The method covers silicon analysis in engine coolant concentrates with silicon content from 200 ppm to 500 ppm. Analyzing samples outside this range is possible with appropriate adjustments to sample size.
• Technique: Uses atomic absorption spectroscopy combined with a nitrous oxide-acetylene flame, eliminating issues related to reagent instability commonly found in photometric approaches.
• Apparatus and Reagents:
  • Atomic absorption spectrometer
  • Hollow-cathode silicon lamp
  • Standard silicon solution
  • Ethylene glycol or propylene glycol (to match coolant type)
  • Sodium hydroxide
  • Distilled or equivalent-quality water
• Accuracy and Precision: The method delivers accuracy and precision comparable to photometric methods, with repeatability and reproducibility validated by industry benchmarks.
• Calibration: Preparation of working standards (0, 20, 40, 60 mg/L Si) ensures calibration curves directly relate absorbance to silicon concentration.
• Units: All results are expressed using SI (International System of Units) for global compatibility.
• Safety Note: Users are responsible for ensuring safe laboratory practices and compliance with regulatory guidelines.

Applications

ASTM D6129-97(2021) is valuable for a range of practical applications in the automotive, industrial, and laboratory sectors:

• Quality Assurance: Ensures that engine coolant concentrates meet manufacturer specifications for silicon content, contributing to optimal heat exchange and corrosion protection.
• Research and Development: Enables laboratories to evaluate new coolant formulations by accurately measuring silicon, an essential additive or impurity.
• Inspection and Compliance: Used by regulatory bodies and third-party labs for monitoring product conformity and supporting warranty claims.
• Production Monitoring: Helps manufacturers monitor silicon levels during the blending process, reducing risks of product failures and equipment wear.

Related Standards

Professionals may reference the following related ASTM and industry standards to complement testing and sampling procedures:

• ASTM D1176 - Practice for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antirusts for Testing Purposes
• Reagent Chemicals, American Chemical Society Specifications
• ISO standards - For laboratories operating in international markets (seek relevant ISO standards for spectroscopic analysis)
• WTO TBT Committee Guidance - Developed in accordance with World Trade Organization Technical Barriers to Trade principles

These related guidelines support a comprehensive quality management system for engine coolant production and testing.

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Keywords: ASTM D6129, silicon determination, engine coolant analysis, atomic absorption spectroscopy, coolant concentrates, laboratory standards, automotive coolant testing, chemical analysis standards, silicon spectroscopy.

Standards Content (Sample)

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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