ASTM_D_4374_-_00.pdf

Designation:D 4374 00An American National StandardStandard Test Methods forCyanides in WaterAutomated Methods for Total Cyanide,Acid dissociable Cyanide,and Thiocyanate1This standard is issued under the fixed designation D 4374;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 These test methods cover the determination of differentspecies of cyanides and thiocyanate in water and waste water,namely acid dissociable cyanide,total cyanide,and thiocyanate(1).21.1.1 Total Cyanide This test method determines all theacid dissociable cyanides and the strong metal-cyano-complexes,such as ferrocyanide Fe(CN)64,ferricyanideFe(CN)63,hexacyanocolbaltate Co(CN)63,and those ofgold and platinum.1.1.2 Acid Dissociable CyanideThis test method basicallydetermines free cyanides,as CNand HCN,and weakmetal-cyano-complexes such as Cd(CN)42and Mn(CN)63.Iron complexes are not included.1.1.3 Cyanide complexes,strong complexes like those ofiron,cobalt,etc.,can be determined by difference,that is,cyanide complexes=total cyanides acid dissociable cya-nides.1.1.4 Thiocyanate This test method determines the thio-cyanate as the difference between another measurement thatincludes total cyanide plus thiocyanate and the value of totalcyanide,thatis,thiocyanate=totalcyanideplusthiocyanate total cyanide.1.2 Cyanates and cyanogen halides are not detected.Cyano-gen chloride hydrolyzes to cyanate at the pH of samplepreservation($12).1.3 Most of the organo-cyano-complexes are not measured,with the exception of the weak cyanohydrins.1.4 These test methods apply to different types of water,waste water(raw sewage,sludge,and effluent),sludge,someindustrial waste,and sediments.Sample matrixes should beevaluated by the user.The reported precision and bias(seeSection 16)may not apply to all samples.1.5 The values stated in SI units are to be regarded as thestandard.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 and health practices and determine the applica-bility of regulatory limitations prior to use.For specificprecautionary statements,see Section 9.2.Referenced Documents2.1 ASTM Standards:D 1129 Terminology Relating to Water3D 1193 Specification for Reagent Water3D 2036 Test Methods for Cyanides in Water4D 3370 Practices for Sampling Water from Closed Con-duits3D 3856 Guide for Good Laboratory Practices in Laborato-ries Engaged in Sampling and Analysis of Water3D 3864 Guide for Continual On-Line Monitoring Systemsfor Water Analysis3D 4193 Test Method for Thiocyanate in Water4D 4210 Practice for Intralaboratory Quality Control Proce-dures and a Discussion on Reporting Low-Level Data3D 5788 Guide for Spiking Organics Into Aqueous Samples3D 5789 Practice for Writing Quality ControL Specificationsfor Standard Test Methods for Organic Constituents33.Terminology3.1 DefinitionsFor definition of terms relating to water,refer to Terminology D 1129.3.2 Definitions of Terms Specific to This Standard:3.2.1distillation ratio,%=volume of distilled portion of sampletotal volume of acidified sample3 1001These test methods are under the jurisdiction of ASTM Committee D19 onWater and are the direct responsibility of Subcommittee D19.06 on Methods forAnalysis for Organic Substances in Water.Current edition approved June 10,2000.Published September 2000.Originallypublished as D 4374 84.Last previous edition D 4374 98.2The boldface numbers in parentheses refer to the list of references at the end ofthe text.3Annual Book of ASTM Standards,Vol 11.01.4Annual Book of ASTM Standards,Vol 11.02.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.4.Summary of Test Method4.1 Some automated continuous flow modules are used(seeGuide D 3864)in addition to the newly developed on-line thinfilm distillation(2)and ultraviolet(UV)irradiation(3).4.2 Three factors control the separation of cyanides from thesamples,namely(a)UV irradiation,(b)pH and acidification,and(c)temperature and time of distillation(see 7.4,7.5,and7.3).4.3 Acidification is made to pH 1 mg/L distills over with the cyanide causingnegative interference.Most samples do not contain mercury atthis high level.6.10 Potential Cyanide-Forming Materials:6.10.1 Several substances,namely cyanate,nitrobenzene,urea,thiourea,glycine,and cysteine,were investigated todetermine if they hydrolyze or break down under the experi-mental conditions and interfere with the cyanide determination.6.10.2 None of these materials gave interferences in the aciddissociable cyanide measurement.6.10.3 Only few sulfur-containing substances gave variablepositive interferences with the total cyanide determinat