1、Designation:D612997(Reapproved 2021)Standard Test Method forSilicon in Engine Coolant Concentrates by AtomicAbsorption Spectroscopy1This standard is issued under the fixed designation D6129;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revi
2、sion,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of silicon inthe range from 200 ppm to 500 ppm in engine coolant
3、concentrates by atomic absorption.This method is as accurateand precise as photometric methods,while requiring consider-ably less operator time and avoiding problems with reagentinstability.1.1.1 Coolants with silicon content outside of this rangemay be analyzed by this method by suitably adjusting
4、thesample size.Care should be taken to ensure that the glycolcontent of the working standards corresponds to that of thesample solution being analyzed.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard does not
5、 purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standar
6、d was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenc
7、ed Documents2.1 ASTM Standards:2D1176 Practice for Sampling and Preparing Aqueous Solu-tions of Engine Coolants orAntirusts for Testing Purposes3.Summary of Test Method3.1 The sample is dissolved in water and the silicon contentis determined from a standard curve established at the time thesample is
8、 run.An atomic absorption spectrometer with anitrous oxide-acetylene flame is used.4.Apparatus4.1 Atomic Absorption Spectrometer,with nitrous oxide-acetylene flame.4.2 Hollow-Cathode Lamp,for silicon.5.Reagents5.1 Reagent grade chemicals shall be used in all tests.35.2 References to water shall be u
9、nderstood to mean dis-tilled water or water of equal quality.5.3 Standard Silicon Solution,1000 mg/L(see Note 1).5.4 Ethylene Glycol(propylene glycol should be used whenanalyzing PG-based coolants).5.5 Sodium Hydroxide,5%in water(see Note 1).Whenpreparing from solid sodium hydroxide avoid prolonged
10、expo-sure to the atmosphere.DO NOT STORE IN GLASS.5.6 Working standards:0 mg L,20 mg L,40 mg L,and60 mg L silicon.5.6.1 Prepare these solutions by pipeting 2.0 mL,4.0 mL,and 6.0 mL of the 1000 mg/L standard silicon solution intoseparate 100 mL volumetric flasks.Add 10.0 mL of ethyleneglycol and 2.0
11、mL of 5%sodium hydroxide solution to eachflask and dilute to volume with water.Prepare the zero standardsolution by adding 10.0 mL ethylene glycol and 2.0 mL 5%sodium hydroxide solution to another 100 mL volumetric flaskand diluting to volume with water.NOTE1Standard silicon solutions and sodium hyd
12、roxide solutions areavailable from most laboratory supply companies.1This test method is under the jurisdiction of ASTM Committee D15 on EngineCoolants and Related Fluids and is the direct responsibility of SubcommitteeD15.04 on Chemical Properties.Current edition approved Sept.1,2021.Published Sept
13、ember 2021.Originallyapproved in 1997.Last previous edition approved in 2015 as D6129-97(2015).DOI:10.1520/D6129-97R21.2For 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 th
14、e standards Document Summary page onthe ASTM website.3Reagent 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,Do
15、rset,U.K.,and the United States Pharmacopeiaand National Formulatory,U.S.Pharmacopeial Convention,Inc.(USPC)Rockville,MD.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internatio
16、nally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.16.Sampling6.1 Sample material in accordance with Practice D1176.7.Procedure7.1 To the nearest 0.001 g,weigh 5 g of sample into a 50 mLvolumetric flask.Dissolve in and dilute to volume with water.7.2 Using the nitrous oxide-acetylene flame,optimize theinstr
