ASTM_D_7304_-_22.pdf

Designation:D730422Standard Test Method forDetermination of Denatonium Benzoate in Engine Coolantby HPLC1This standard is issued under the fixed designation D7304;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,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 chemical analysis of enginecoolant for denatonium benzoate(DNB)by high-performanceliquid chromatography(HPLC).DNB is added to potentiallyrender engine coolant unpalatable to animals and humans.Thisanalytical method was designed for the analysis of DNB and isnot valid for any other bittering agents such as denatoniumsaccharide.1.2 This test method is applicable to both new and usedcoolants.1.3 Coelution of other ions may cause interferences in thedetection of the denatonium cation.In the case of unfamiliarformulations,identification verification should be performedby either or both fortification and dilution of the sample matrixwith denatonium ion.1.4 The values stated in SI units are to be regarded asstandard.The values given in parentheses are for informationonly.1.5 This standard does not 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.1.6 This international standard 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.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1176 Practice for Sampling and Preparing Aqueous Solu-tions of Engine Coolants orAntirusts for Testing PurposesE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Summary of Test Method3.1 The denatonium benzoate analysis is achieved by anHPLC method,where a weight of engine coolant is placed inan auto-sampler vial and mixed with a known volume ofde-ionized water.The auto-sampler vial is placed in a HPLCautosampler and the measurement of denatonium benzoate isperformed using a C-18 reverse phase column attached to anultraviolet detector.The ultraviolet detector is used to measurethe response of the DNB active ingredients(denatonium andbenzoate)in the engine coolant after they have been separatedin the reverse phase column.The denatonium and benzoateresponses are compared to responses of known concentrationsand the HPLCs computer calculates the amount of DNBpresent in the coolant.4.Significance and Use4.1 This test method provides for the qualitative and quan-titative determination of denatonium benzoate in engine cool-ant in milligrams per litre to low percent range and requiresapproximately 1 mL per test,with results available in less than10 min.Denatonium benzoate is a compound composed of aquaternary ammonium cation,denatonium and an inert anion,benzoate.In solution the denatonium benzoate exists in equi-librium between the denatonium benzoate compound,thedenatonium cation and benzoate anion.By slightly adjustingthe pH of the solution to be more acidic(pH 4.6)theequilibrium will be shifted to the direction of forming moredenatonium and benzoate ions in the solution.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 March 1,2022.Published April 2022.Originallyapproved in 2006.Last previous edition approved in 2016 as D730416.DOI:10.1520/D7304-22.2For 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 the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally 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.15.Interferences5.1 Interferences can be caused by substances with similarretention times,especially if they are in high concentrationcompared to the analyte of interest,denatonium ion.Knownchromatographic interferences have been determined and theanalysis modified to minimize any co-elution of interferingpeaks.The eluent st