ASTM_D_7284_-_20.pdf

Designation:D728420Standard Test Method forTotal Cyanide in Water by Micro Distillation followed byFlow Injection Analysis with Gas Diffusion Separation andAmperometric Detection1This standard is issued under the fixed designation D7284;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 is used to determine the concentrationof total cyanide in an aqueous wastewater or effluent.This testmethod detects the cyanides that are free(HCN and CN)andstrong-metal-cyanide complexes that dissociate and releasefree cyanide when refluxed under strongly acidic conditions.1.2 This test method may not be applicable to processsolutions from precious metals mining operations.1.3 This procedure is applicable over a range of approxi-mately 2 to 500 g/L(parts per billion)total cyanide.Higherconcentrations can be measured with sample dilution or lowerinjection volume.1.4 The determinative step of this test method utilizes flowinjection with amperometric detection based on Test MethodD6888.Prior to analysis,samples must be distilled with amicro-distillation apparatus described in this test method orwith a suitable cyanide distillation apparatus specified in TestMethods D2036.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 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.Specific hazard statements are given in 8.6 and Section 9.1.7 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:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2036 Test Methods for Cyanides in WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3856 Guide for Management Systems in LaboratoriesEngaged in Analysis of WaterD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisD6696 Guide for Understanding Cyanide SpeciesD6888 Test Method for Available Cyanides with LigandDisplacement and Flow InjectionAnalysis(FIA)UtilizingGas Diffusion Separation and Amperometric DetectionD7365 Practice for Sampling,Preservation and MitigatingInterferences in Water Samples for Analysis of CyanideE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard,refer toTerminology D1129 and Guide D6696.3.2 Definitions of Terms Specific to This Standard:3.2.1 total cyanide,ntotal cyanide is an analytically de-fined term that refers to the sum total of all of the inorganicchemical forms of cyanide that dissociate and release freecyanide when refluxed under strongly acidic conditions.3.2.1.1 DiscussionTotal cyanide is determined analyti-cally through strong acid distillation or UV radiation followedby analysis of liberated free cyanide on aqueous samplespreserved with NaOH(pH12).In water,total cyanide includesthe following dissolved species:free cyanide,weak aciddissociable metal cyanide complexes and strong metal cyanidecomplexes.Also,some of the strong metal cyanide complexes,1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.06 on Methods forAnalysis forOrganic Substances in Water.Current edition approved Aug.1,2020.Published August 2020.Originallyapproved in 2008.Last previous edition approved in 2017 as D7284 13(2017).DOI:10.1520/D7284-20.2For 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.such as those of gold,cobalt and platinum,might not be fullyrecovered during the total cyanide analytical