1、Designation: D7511 12 (Reapproved 2017)1Standard Test Method forTotal Cyanide by Segmented Flow Injection Analysis, In-LineUltraviolet Digestion and Amperometric Detection1This standard is issued under the fixed designation D7511; the number immediately following the designation indicates the year o
2、foriginal 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.1NOTEWarning notes were editorially updated throughout in July 2017.1.
3、 Scope1.1 This test method is used for determining total cyanide indrinking and surface waters, as well as domestic and industrialwastes. Cyanide ion (CN), hydrogen cyanide in water(HCN(aq), and the cyano-complexes of zinc, copper,cadmium, mercury, nickel, silver, and iron may be determinedby this t
4、est method. Cyanide ions from Au(I), Co(III), Pd(II),and Ru(II) complexes are only partially determined.1.2 The method detection limit (MDL) is 1.0 g/L cyanideand the minimum level (ML) is 3 g/L. The applicable range ofthe method is 3 to 500 g/L cyanide using a 200-L sampleloop. Extend the range to
5、analyze higher concentrations bysample dilution or changing the sample loop volume.1.3 This test method can be used by analysts experiencedwith equipment using segmented flow analysis (SFA) and flowinjection analysis (FIA) or working under the close supervisionof such qualified persons.1.4 The value
6、s 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 safe
7、ty and health practices and determine the applica-bility of regulatory limitations prior to use. Specific hazardstatements are given in 8.5 and Section 9.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Dec
8、ision 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 Te
9、st Methods for Cyanides in WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD3856 Guide for Management Systems in LaboratoriesEngaged in Analysis of WaterD4210 Practice for Intralabor
10、atory Quality Control Proce-dures and a Discussion on Reporting Low-Level Data(Withdrawn 2002)3D5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisD6696 Guide for Understanding Cyanide SpeciesD7365 Practice for Sampling, Preservation and MitigatingInt
11、erferences 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 total cyanide, nrefers to all cyanide-containing com-pounds in a s
12、ample, including free cyanide, WAD cyanidecompounds, and strong metal cyanide complexes.4. Summary of Test Method4.1 Prior to analysis, treat the sample to remove potentialinterferences (Sections 4 and 8). Ultraviolet (UV) digestionreleases cyanide from cyanide complexes. Acid addition con-verts cya
13、nide ion to hydrogen cyanide gas (HCN), whichpasses under a gas diffusion membrane. The hydrogen cyanide1This 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 edit
14、ion approved July 1, 2017. Published July 2017. Originally approvedin 2009. Last previous edition approved in 2012 as D7511 12. DOI: 10.1520/D7511-12R17E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AST
15、MStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis int
16、ernational 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) C
17、ommittee.1gas diffuses through the membrane into an alkaline receivingsolution, where it converts back to cyanide ion. A silverworking electrode, silver/silver chloride reference electrode,and platinum/stainless steel counter electrode at an appliedpotential of zero volt amperometrically monitor the
18、 cyanideion. The current generated is proportional to the cyanideconcentration present in the original sample.4.2 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 estab
19、lished to require the monitoring ofcyanide in industrial and domestic wastewaters and surfacewaters.45.2 This test method is applicable for natural water, salinewaters, and wastewater effluent.5.3 This test method may be used for process control inwastewater treatment facilities.5.4 The spot test ou
20、tlined in Test Methods D2036, AnnexA1, can be used to detect cyanide and thiocyanate in water orwastewater, and to approximate its concentration.6. Interferences6.1 Test method interferences can be caused by contami-nants in the reagents, reagent water, glassware, etc., which maybias the results. Ta
21、ke care to keep all such items free ofcontaminants.6.2 Sulfide and sulfide-containing compounds are positiveinterferents in this test method. When acidified, sulfide formshydrogen sulfide, which passes through the gas diffusionmembrane and produces a signal at the silver electrode. Inaddition, sulfi
22、de ion reacts with cyanide ion in solution toreduce its concentration over time. Treat samples containingsulfide according to 11.4. During UV digestion, some sulfurcompounds may produce sulfide. TA2 reagent contains asulfide scrubber that can remove up to 50 mg/L S2from thesystem prior to amperometr
23、ic detection.6.3 Treat sample containing water-soluble aldehydes, suchas formaldehyde or acetaldehyde, by adding ethylenediaminesolution.6.4 Remove oxidizing agents that decompose cyanides byadding ascorbic acid, or sodium arsenite.6.5 Thiocyanate can produce positive interference whenthey decompose
24、 to cyanide by UV irradiation or oxidation.This test method uses 312 nm as the irradiation wavelength,which keeps thiocyanate interference from UV irradiationminimal. Use of Total Acid ReagentModified, TA1M (see8.21) minimizes interference from thiocyanate.6.6 High concentrations of carbonate can re
25、sult in a nega-tive response in the amperometric detector when carbondioxide diffuses across the gas diffusion membrane into thealkaline receiving solution, reducing its pH. Treat effluentsfrom high carbonate containing wastes, such as coal gasifica-tion waste and atmospheric emission scrub water, w
26、ith hy-drated lime to stabilize the sample.6.7 High concentrations of surfactants interfere by changingthe characteristics of the gas diffusion membrane, allowingacid solution to pass through the membrane and enter thedetector.6.8 Nitrate and nitrite if treated with sulfamic acid do notinterfere in
27、this test method.6.9 Sodium sulfite, sulfur dioxide, or sodium bisulfite do notinterfere at up to 2000 ppm SO3.6.10 Sodium Thiosulfate exhibits a slight positive bias atconcentrations above 200 ppm. This positive bias may beremoved by increasing the amount of Bismuth Nitrate in theTA2 reagent.6.11 S
28、amples containing particulates should be filtered priorto analysis. Extract and combine filtered extract with originalsample prior to analysis, or measure the filtered extract and theaqueous sample separately and combine results mathemati-cally.7. Apparatus7.1 The instrument should be equipped with
29、a precisesample introduction system, a UV digester with a 312-nm lampand UV transparent digestion coil, a gas diffusion manifoldwith hydrophobic membrane, and an amperometric detectionsystem to include a silver working electrode, an Ag/AgClreference electrode, and a Pt or stainless steel counter ele
30、c-trode. Examples of the apparatus schematics are shown in Fig.1. Example instrument settings are shown in Table 1.5NOTE 1The instrument settings in Table 1 are only examples. Theanalyst may modify the settings as long as performance of the test methodhas not been degraded. Contact the instrument ma
31、nufacturer for recom-mended instrument parameters.7.2 An autosampler is recommended but not required toautomate sample injections and increase throughput. Autosamplers are usually available as an option from the instru-ments manufacturer.7.3 Data Acquisition SystemUse the computer hardwareand softwa
32、re recommended by the instrument manufacturer tocontrol the apparatus and to collect data from the detector.7.4 Pump TubingUse tubing recommended by instrumentmanufacturer. Replace pump tubing when worn, or whenprecision is no longer acceptable.7.5 Gas Diffusion MembranesA hydrophobic membranewhich
33、allows gaseous hydrogen cyanide to diffuse from thedonor to the acceptor stream at a sufficient rate to allow440 CFR Part 136.5The sole source of supply of the apparatus known to the committee at this timeis the trademarked CNSolution equipped with an amperometric flow cell, gasdiffusion, and UV dig
34、estion module, available from OI Analytical. If you are awareof alternative suppliers, please provide this information to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.D7511 12 (2017)12detecti
35、on. The gas diffusion membrane should be replacedwhen the baseline becomes noisy or every 1 to 2 weeks.67.6 Use parts and accessories as directed by instrumentmanufacturer.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it
36、 is intended thatall reagents shall conform to the specifications of theAmericanChemical Society, where such specifications are available.7Other grades may be used, provided it is first ascertained thatthe reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of the
37、determination.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean interference free reagentwater conforming to Type I or Type II grade of SpecificationD1193.8.3 Sodium Hydroxide Solution (1.00 M)Dissolve 40 gNaOH in laboratory water and dilute to 1 L.8.4 Acc
38、eptor Solution (0.10 M NaOH)Dissolve 4.0 gNaOH in laboratory water and dilute to 1 L.8.5 Stock Cyanide Solution (1000 g/mL CN)Dissolve2.51 g of KCN and 2.0 g of NaOH in 1 L of water. Standardizewith silver nitrate solution as described in 8.5.1 8.5.4. Storethe solution under refrigeration and check
39、concentration ap-proximately every 6 months and correct if necessary.8(WarningBecause KCN is highly toxic, avoid contact orinhalation.)8.5.1 Pipet 100 mL of Stock Cyanide Solution (see 8.5) intoa 250 mL flask or beaker.8.5.2 Add 0.5 mL of rhodanine indicator solution (see 8.17).8.5.3 Titrate with st
40、andardized silver nitrate solution (see8.18 and 8.18.2) to the first color change from yellow tosalmon pink.8.5.4 Record the results of the titration and calculate thecyanide concentration of the Stock Cyanide Solution accordingto the equation in 8.18.2.8.5.5 Use the actual calculated cyanide concen
41、tration in allsubsequent calculations of working standard concentrations.8.6 Intermediate Cyanide Standards:8.6.1 Intermediate Standard 1 (100 g/mL CN)Pipette10.0 mL of stock cyanide solution (see 8.5) into a 100 mLvolumetric flask containing 1 mL of 1.0 M NaOH (see 8.3).Dilute to volume with labora
42、tory water. Store under refrigera-tion. The standard should be stable for at least 2 weeks.8.6.2 Intermediate Cyanide Solution 2 (10 g/mL CN)Pipette 10.0 mL of Intermediate Cyanide Solution 1 (see 8.6.1)into a 100 mL volumetric flask containing 1.0 mL of 1.00 MNaOH (see 8.3). Dilute to volume with l
43、aboratory water. Thestandard should be stable for at least 2 weeks.8.7 Working Cyanide Calibration StandardsPrepare freshdaily as described in 8.7.1 and 8.7.2 ranging in concentrationfrom 3 to 500 g/L CN.8.7.1 Calibration Standards (20, 50, 100, 200, and 500 g/LCN)Pipette 20, 50, 100, 200, and 500 L
44、 of IntermediateStandard 1 (see 8.6.1) into separate 100 mL volumetric flaskscontaining 1.0 mL of 1.00 M NaOH (see 8.3). Dilute to volumewith laboratory water.8.7.2 Calibration Standards (3 and 10 g/L CN)Pipette30 and 100 L of Intermediate Cyanide Solution 2 (see 8.6.2)6The sole source of supply of
45、the apparatus known to the committee at this timeis OI Analytical Part Number A001520 and Pall Corporation Part NumberM5PU025. If you are aware of alternative suppliers, please provide this informationto ASTM International Headquarters. Your comments will receive careful consid-eration at a meeting
46、of the responsible technical committee,1which you may attend.7Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BD
47、H Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.8Commercially available stock cyanide solutions may be substituted.FIG. 1 Flow Injection Analysis Apparatus 1TABLE 1 Flow Injection Analysis ParametersFIA I
48、nstrument Parameter Recommended Method SettingPump Flow Rates 0.5 to 2 mL/minCycle Period (Total) 90 to 250 s/sampleSample Load Period At least enough time to completely fillthe sample loopReagent Water Rinse Time BetweenSamplesAt least 15 secondsPeak Evaluation Peak height or areaWorking Potential
49、0.0 V versus Ag/AgClD7511 12 (2017)13into separate 100 mL volumetric flasks containing 1.0 mL of1.00 M NaOH (see 8.3). Dilute to volume with laboratorywater.8.8 Cyanide Electrode Stabilization Solution (Approxi-mately 5 ppm as CN)Pipette 500 L of Stock Cyanide (see8.5) into a 100 mL volumetric flask containing 1.0 mL of 1.00M NaOH (see 8.3). Dilute to volume with laboratory water.The solution should be stored under refrigeration.8.9 Acetate BufferDissolve 410 g of sodium acetate trihy-drate (NaC2H3O23H2O) in 500 mL of laboratory
