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r <br />lY~r' 1 <br />' •' 1 ~~ ~ III I II I II I II IIII III <br />999 <br />~~ Designation: D 4374 - 90 <br />Standard Test Methods for <br />Cyanide In Water-Automated Methods For Total Cyanide <br />And Dissociable Cyanide' <br />This standard is issued under the fixed deigna[ion D4374; tht number immcdialely following the designation indicates the ?ear of <br />original adoption or, in the eau of revision, the year of last revision. A number in parentheses indicates she year of last reapprc val. A <br />superscript epsilon (<) indicates an editorial change sintt the lazt revision or reapproval. <br />1. Scope <br />I.I These test methods cover the determination of dif- <br />ferent species of cyanides in water and waste water, namely, <br />dissociable cyanide, and total cyanide (1, 2).2 <br />l.l.l Dissociable Cyanide-This test method basically <br />determines free cyanides, as CN- and HCN, and weak <br />metal-cyano-complexes such as [Cd(CN)4]~- and <br />[Mn(CN)4]3-. Iron complexes are not included. <br />1.1.2 Total Cvanide-This test method determines all the <br />acid dissociable cyanides and the strong metal-cyano- <br />complexes, such as ferrocyanide [Fe(CN)6]4-, ferricyanide <br />[Fe(CN)b]3', hexacyanocobaltate [Co(CN)6]3-, and those of <br />gold and platinum. <br />l.2 Cyanide complexes, like those of iron, cobalt, etc„ can <br />be determined by difference, that is, C anide Com lexes = <br />Total Cyanides -Dissociable Cyani es. <br />otal cyanide measurement includes also all the <br />thiocyanates. However, the thiocyanate could be determined <br />(3, 4, 5) and subtracted if so desired. <br />1.4 Cyanates and cyanogen halides are not detected. <br />cyanogen chloride hydrolyses to cyanate at the pH of sample <br />preservation (a 12). <br />I.5 Most of the organo-cyano-complexes are not mea- <br />sured, with the exception of the weak cyanohydrins. <br />l.6 These test methods apply to different types of water <br />samples, namely drinking water, natural surface and ground <br />water, saline water, raw sewage, treated effluents, and some <br />industrial wastes. Other sample matrixes should be evaluated <br />by the user. The reported precision and biaz (see Section 15) <br />may not apply to other waters. <br />1.7 This standard does not purport to address all of the <br />sajefy problems associated with its use. /t is the responsibility <br />ojt/le user ojthis standard to establish appropriate sajefy and <br />ltealrh practices and determine flee applicabi(ify ojregulatory <br />limitations prior to use. Specific precautions are given in <br />Section 9. <br />2. Referenced Documents <br />2.1 ASTM Standards: <br />D 1 129 Definitions of Terms Relating to Water' <br />D 1193 Specification far Reagent Water3 <br />These test methods are und<r the jurisdiction of ASTM Committee 619 on <br />Wamr and are the direr responsibility of Subcommittee D19.06 on Meshods for <br />Analysis for Orgpnic Subsunces in water. <br />Current edition approved May 25. 1990. Published November 1990. Originally <br />published as D 4174 - 84. lass previous edition D 4374 - 86. <br />-'The boldfatt numbers in parentheses refer to the list of references appended <br />to this sandard. <br />a .4ncual BaoA of.4STAf Standards. Vol 11.01. <br />WX ~~\Y ~Ir~ <br />D 2036 Test Methods for Cyanides in Vlater4 <br />D 3370 Practices for Sampling Water' <br />D 3856 Guide for Good Laboratory Pra~:tices in Laborato- <br />ries Engaged in Sampling and Analysis of Water' <br />D 3864 Guide for Continual On-Line M onitoting Systems <br />for Water Analysis} <br />D4193 Test Method for Thiocvanate in Water" <br />D 4210 Practice for Interlaboratory Quality Control Proce- <br />dures and a Discussion on Reporting Low-Level Data' <br />3. Terminology <br />3.1 Definitions-For definitions of terns, refer to Defini- <br />tions D 1129. <br />3.2 Descriptions ojTerms Specific to T his Standard.' <br />3.2.1 Acid Dissociable Cvanide-Und:r the defined e~- <br />petimental conditions (Sections 4, 10, and I I), this param- <br />eter determines the free cyanides, HCN and CN-, and the <br />weak cyanide complexes. Iron complexes are not included. <br />3.2.2 Total Cvanide-In addition to all the acid <br />dissociable cyanides, the strong cyanide complexes are in- <br />cluded, such as those of iron and cobalt. <br />3.2.3 Distillation Ratio, % _ <br />Volume of Distilled Portion of Sarr ple x 100 <br />Total Sample Volume <br />4. Summary of Test Methods <br />4.1 Some automated continuous flow modules are used <br />(see Guide D 3864) in addition to the newly developed on- <br />line Thin Film Distillation (6) and Ultra~riolet Irradiation. <br />4.2 Three factors control the separation of cyanides from <br />the samples, namely (a) acidification, (bl air stripping. anal <br />(c) thin film distillation (7.2 and 7.3). The classic use ai <br />condensers in distillation units was found to be disadvanu- <br />geous, and has been eliminated, because a considerable <br />amount of the liberated HCN gas is reFl axed back with the <br />condensed water and thus not recovered. <br />4.3 Acidification is made to pH<I, but the sample <br />exposure to heat treatment in the continuous thin film <br />distillation is very short (few seconds). Tt1us the liberation ni <br />HCN is only from the free cyanides amt the weak cyanide <br />complexes, that is, the dissociable cyanides, and no[ from the <br />strong complexes. <br />4.4 For total cyanides the breakdown of the strong c~3- <br />nide complexes, prior to the thin film distillation, is achietr'd <br />by ultraviolet irradiation (7). <br />4.5 Absorption of the liberated HCl` gas is carried ool <br />Annual BooA ofASTtif Standards, Vol 11.02. <br />104 <br />using a gl <br />(7.4). <br />4.6 Col• <br />is made t <br />developed <br />use a SSt. <br />4.7 The <br />methods i <br />concentrat <br />allows for <br />5. Signific <br />5.1 Cya <br />to fish ar <br />chemistry <br />cyanide sp <br />rides in in <br />concern. S <br />uous mon <br />wastes. Tn. <br />tools for sy <br />