1、Designation:D688816Standard Test Method forAvailable Cyanides with Ligand Displacement and FlowInjection Analysis(FIA)Utilizing Gas Diffusion Separationand Amperometric Detection1This standard is issued under the fixed designation D6888;the number immediately following the designation indicates the
2、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 method is used to determine the concentration ofavaila
3、ble inorganic cyanide in an aqueous wastewater oreffluent.The method detects the cyanides that are free(HCNand CN-)and metal-cyanide complexes that are easily disso-ciated into free cyanide ions.The method does not detect theless toxic strong metal-cyanide complexes,cyanides that arenot“amenable to
4、chlorination.”1.2 Total cyanide can be determined for samples that havebeen distilled as described in Test Methods D2036,TestMethod A,Total Cyanides after Distillation.The cyanidecomplexes are dissociated and absorbed into the sodiumhydroxide capture solution,which can be analyzed with thistest meth
5、od;therefore,ligand exchange reagents from Sections8.12 and 8.13 would not be required when determining totalcyanide after distillation.1.3 This procedure is applicable over a range of approxi-mately 2 to 400 g/L(parts per billion)available cyanides.Higher concentrations can be analyzed by dilution
6、or lowerinjection volume.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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 stand
7、ard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.Specific hazardstatements are given in 8.6 and Section 9.2.Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent Wate
8、rD2036 Test Methods for Cyanides in 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 SpeciesD7365 Practice for Sampling,Preserv
9、ation and MitigatingInterferences in Water Samples for Analysis of Cyanide3.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 available cyanides,nInorganic cyanides that a
10、refree(HCN and CN-)and metal-cyanide complexes that areeasily dissociated into free cyanide ions.3.2.1.1 DiscussionAvailable cyanide does not include theless toxic strong metal-cyanide complexes,cyanides that arenot“amenable to chlorination”and includes weak acid disso-ciable or weak and dissociable
11、(WAD)cyanides for use in theimplementation of International Cyanide Management Code.4.Summary of Test Method4.1 Complex cyanides bound with nickel or mercury arereleased by ligand displacement by the addition of a liganddisplacement agent,when necessary.4.2 Other weak and dissociable cyanide species
12、 do notrequire ligand displacement.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 Feb.1,2016.Published June 2016.Originallyapproved in 200
13、3.Last previous addition approved in 2009 as D6888 09.DOI:10.1520/D6888-16.2For 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
14、 website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.3 The sample is introduced into a flow injection analysis(FIA)system where it is acidified to form hydrogen cyanide(HCN).The hydrogen cyanide gas diffuses through a hydro-phobic g
15、as diffusion membrane,from the acidic donor streaminto an alkaline acceptor stream.4.4 The captured cyanide is sent to an amperometric flow-cell detector with a silver-working electrode.In the presence ofcyanide,silver in the working electrode is oxidized at theapplied potential.The anodic current m
16、easured is proportionalto the concentration of cyanide in the standard or sampleinjected.4.5 Calibrations and data are processed with the instru-ments data acquisition software.5.Significance and Use5.1 Cyanide and hydrogen cyanide are highly toxic.Regu-lations have been established to require the monitoring ofcyanide in industrial and domestic wastes and surface waters.35.2 This test method is applicable for natural water,salinewaters,metallurgical process solutions,and wastewater efflu-ent.5.3
