ASTM_D_6888_-_09.pdf

Designation:D688809Standard Test Method forAvailable Cyanide 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 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 ofavailable 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 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 method;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 cyanide.Higher concentrations can be analyzed by dilution 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 standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.Specific hazardstatements are given in Note 2 and Section 9.2.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 WaterD4375 Practice for Basic Statistics in Committee D19 onWaterD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisD6696 Guide for Understanding Cyanide SpeciesD7365 Practice for Sampling,Preservation and MitigatingInterferences in Water Samples for Analysis of CyanideE60 Practice for Analysis of Metals,Ores,and RelatedMaterials by SpectrophotometryE275 Practice for Describing and Measuring Performance ofUltraviolet and Visible Spectrophotometers3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method,referto Terminology D1129 and Guide D6696.3.1.2 available cyanide,nInorganic cyanides that are free(HCN and CN-)and metal-cyanide complexes that are easilydissociated into free cyanide ions.Available cyanide does notinclude the less toxic strong metal-cyanide complexes,cya-nides that are not“amenable to chlorination.”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 Oct.1,2009.Published October 2009.Originallyapproved in 2003.Last previous addition approved in 2004 as D6888 04.DOI:10.1520/D6888-09.2For 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 States1 4.Summary of Test Method4.1 Complex cyanides bound with nickel or mercury arereleased by ligand displacement by the addition of a liganddisplacement agent prior to analysis.4.2 Other weak and dissociable cyanide species do notrequire ligand displacement.4.3 The treated sample is introduced into a flow injectionanalysis(FIA)system where it is acidified to form hydrogencyanide(HCN).The hydrogen cyanide gas diffuses through ahydrophobic gas diffusion membrane,from the acidic donorstream into 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 measured 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 w