1、Designation: D 7365 07Standard Practice forSampling, Preservation and Mitigating Interferences inWater Samples for Analysis of Cyanide1This standard is issued under the fixed designation D 7365; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f 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 This practice is applicable for the collection and pres-ervation of water samples for the ana
3、lysis of cyanide. Thispractice also addresses the mitigation of known interferencesprior to the analysis of cyanide.1.2 The sampling, preservation and mitigation of interfer-ence procedures described in this practice are recommendedfor the analysis of total cyanide, available cyanide, weak aciddisso
4、ciable cyanide, and free cyanide by Test Methods D 2036,D 4282, D 4374, D 6888, D 6994, and D 7237. This practicecan also be applied to other cyanide methods, for example, USEPA Method 335.4 and Standard Methods 4500-CN-C.1.3 The values stated in SI units are to be regarded asstandard. No other unit
5、s of measurement are included in thisstandard.1.4 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 regul
6、atory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 1293 Test Methods for pH of WaterD 2036 Test Methods for Cyanides in WaterD 3370 Practices for Sampling Water from Closed ConduitsD 3694 Practices for
7、 Preparation of Sample Containers andfor Preservation of Organic ConstituentsD 3856 Guide for Good Laboratory Practices in Laborato-ries Engaged in Sampling and Analysis of WaterD 4282 Test Method for Determination of Free Cyanide inWater and Wastewater by MicrodiffusionD 4374 Test Methods for Cyani
8、des in WaterAutomatedMethods for Total Cyanide, Weak Acid Dissociable Cya-nide, and ThiocyanateD 4411 Guide for Sampling Fluvial Sediment in MotionD 4840 Guide for Sample Chain-of-Custody ProceduresD 4841 Practice for Estimation of Holding Time for WaterSamples Containing Organic and Inorganic Const
9、ituentsD 6888 Test Method for Available Cyanide with LigandDisplacement and Flow Injection Analysis (FIA) UtilizingGas Diffusion Separation and Amperometric DetectionD 6994 Test Method for Determination of Metal CyanideComplexes in Wastewater, Surface Water, Groundwaterand Drinking Water Using Anion
10、 Exchange Chromatogra-phy with UV DetectionD 6696 Guide for Understanding Cyanide SpeciesD 7237 Test Method for Aquatic Free Cyanide with FlowInjection Analysis (FIA) Utilizing Gas Diffusion Separa-tion and Amperometric Detection2.2 U.S. EPA Methods:3EPA OIA-1677EPA Method 335.2EPA Method 335.42.3 A
11、PHA Standard:4Standard Methods 4500-CN Methods C, D, E, F, G, and I2.4 USGS Methods:5USGS I-3300-85USGS I-4302-853. Terminology3.1 Definitions:1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.06 on Methods for Analysis forOrg
12、anic Substances in Water.Current edition approved Aug. 1, 2007. Published August 2007.2For 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
13、 page onthe ASTM website.3Available from United States Environmental Protection Association (EPA),Ariel Rios Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20460, www.ep-a.gov.4Standard Methods for the Examination of Water and Wastewater, 21st edition(2005),American Public HealthAssociation (APHA
14、), 800 I Street, NWWashington,DC 20001, www.apha.org.5Available from United States Geological Survey, 12201 Sunrise Valley Drive,Reston, VA, 20192, www.usgs.gov.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.For definitions of terms
15、 used in this practice, refer toTerminology D 1129 and Guide D 6696.3.2 In this practice, refrigeration shall designate storing thesample between its freezing point and 6C.4. Summary of Practice4.1 Samples are collected in appropriate containers, miti-gated for known interferences, and stabilized wi
16、th sodiumhydroxide prior to analysis.5. Significance and Use5.1 Cyanide is routinely analyzed in water samples, often todemonstrate regulatory compliance; however, improper samplecollection or pretreatment can result in significant positive ornegative bias potentially resulting in unnecessary permit
17、 vio-lations or undetected cyanide releases into the environment.6. Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in this practice. Unless otherwise indicated, it is intendedthat all reagents shall conform to the specifications of theCommittee on Analytical Reagent
18、s of the American ChemicalSociety, where such specifications are available.6Other gradesmay be used, provided it is first ascertained that the reagent isof sufficiently high purity to permit its use without lesseningthe accuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, ref
19、erencesto water shall be understood to mean reagent water that meetsthe purity specifications of Type I or Type II water, presentedin D 1193.6.3 Acetate BufferDissolve 410 g of sodium acetate tri-hydrate (NaC2H3O23H2O) in 500 mL of water. Add glacialacetic acid to yield a solution pH of 4.5, approxi
20、mately 500mL.6.4 Lead Acetate Test StripsTurns black in presence ofsulfides. Moisten the paper with acetate buffer prior to use.Lead acetate test strips have been shown to be sensitive toabout 50 mg/L S2-.6.5 Potassium Iodide (KI) Starch Test PaperTurns blue inpresence of free chlorine. Commercial a
21、lternative test stripsmay be used if they are shown to be at least as sensitive as theKI starch test strips.6.6 pH Indicator Test StripspH indicator test strips ca-pable of changing color at 0.5 pH units in the range of pH 10to 14. More than one test strip may be necessary to cover thisrange.6.7 Sod
22、ium Hydroxide Solution (5 % wt/vol)Ina1Lvolumetric flask, dissolve 50 g NaOH in reagent water anddilute to volume.6.8 Sodium Hydroxide Solution (50 % wt/vol)In a beaker,dissolve 50 g NaOH in reagent water not to exceed 100 mLtotal volume, then transfer to a 100-mL volumetric flask anddilute to volum
23、e. WarningThis is an exothermic reactionand the solution will become very hot while being prepared. Itis recommended to place the solution in a water bath to cool.6.9 Hydrated LimeCa(OH)2powder.6.10 Cadmium chloride, CdCl2.6.11 Ethylenediamine (EDA)6.12 Reducing AgentsSodium thiosulfate (Na2S2O3),as
24、corbic acid, sodium arsenite (NaAsO2), or sodium borohy-dride (NaBH4).6.13 Filter Paper or Syringe equipped with Leur-LockFiltersUnless specified, 0.45 m pore size.6.14 Acidification ReagentsConcentrated hydrochloricacid (HCl) or concentrated sulfuric acid (H2SO4).6.15 Sample BottlesSee section 8.2
25、for further informa-tion about sample bottles.7. Hazards7.1 WarningBecause of the toxicity of cyanide, greatcare must be exercised in its handling. Acidification of cyanidesolutions produces toxic hydrocyanic acid (HCN). Adequateventilation is necessary when handling cyanide solutions and afume hood
26、 should be utilized whenever possible.7.2 WarningMany of the reagents used in these testmethods are highly toxic. These reagents and their solutionsmust be disposed of properly.8. Procedure8.1 Laboratory personnel and field samplers should followthe practices described in Guide D 3856. When sampling
27、closed conduits such as process streams refer to PracticeD 3370. When sampling fluvial sediment in motion or openchannel flow refer to Guide D 4411. It is recommended toconsult with the analytical laboratory prior to collectingsamples to ensure the proper sample volume, containers,preservatives, etc
28、., as these parameters may vary depending onthe analytical methods used to measure the cyanide.8.2 Sample Containers:8.2.1 Sample containers shall be made of materials that willnot contaminate the sample, cleaned thoroughly to remove allextraneous surface contamination prior to use. Chemicallyresist
29、ant glass containers are suitable as well as rigid orcollapsible plastic containers made of polyethylene or polypro-pylene.8.2.2 Virgin commercially cleaned containers certified to befree of contamination are recommended; otherwise, washcontainers with soap or biodegradable detergent if required,the
30、n dry by draining. For further information on samplecontainers, see Practices D 3694.8.2.3 Samples should be collected and stored in dark bottlesto minimize exposure to ultraviolet radiation.8.3 Sample Collection, Preservation, and Mitigation ofInterferences:8.3.1 Collect a sample volume that is suf
31、ficient to theanalytical method into a sample bottle described above. If therequired sample volume is not specified, usually 1Lis sufficientfor most analytical test methods, however, flow injection andautomated methods usually consume considerably less samplevolume than manual methods.6Reagent Chemi
32、cals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand Nationa
33、l Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D73650728.3.2 Certain sample matrices may require immediateanalysis to avoid cyanide degradation due to interferences.While holding times are specified in this practice, it isrecommended to estimate the actual holding time for eac
34、hsample matrix as described in Practice D 4841. A holding timestudy is required for any sample matrix showing evidence thatthe holding time is less than presented in this practice. Potentialinterferences and their corresponding analytical methods areshown in Table 1. In the absence of interference,
35、simplecyanides such as HCN, KCN, and NaCN are determinedreadily by each of the determinative steps, however, to deter-mine “total” cyanide, metal cyanide bonds must be broken andcyanide separated to produce simple cyanide. In most totalcyanide methods, this is accomplished by distillation from acids
36、olution. Although distillation is assumed to eliminate or atleast minimize most interferences, the high temperature andstrong acid solutions can potentially introduce significantpositive or negative bias. Interferences for total cyanide bydistillation are listed in Tables 2 and 3. Interferences are
37、alsodependent on the determinative step, which are shown in Table4.8.3.3 There may be interferences that are not mitigated bythis procedure. Any removal or suppression of interferencemay be employed, provided the laboratory demonstrates that itmore accurately measures cyanide through quality control
38、measures described in the analytical test method. Any removaltechnique not described in this practice or the analytical testmethod should be documented along with supporting data.8.3.4 If the sample can be analyzed within 48 h and sulfideis not present, adjust the pH to 1213 with sodium hydroxide(fo
39、r example, 5 % NaOH or 50 % NaOH). For aquatic freecyanide by Test Method D 7237, adjust to pH 11 as specified inthe test method. Verify the pH of each sample with pHindicator test strips or by Test Methods D 1293. Refrigerate thesample and analyze within 48 h.8.3.5 Otherwise, to extend the holding
40、time to 14 days andmitigate interferences, treat the sample immediately using anyor all of the following techniques as necessary, followed byadjustment of the sample to pH 1213 and refrigeration.8.3.6 SulfideTest for the presence of sulfide by placing adrop of sample on a lead acetate test strip tha
41、t has beenpreviously moistened with acetate buffer. If the test strip turnsblack, sulfide is present (above 50 mg/L S2-) and treatment isnecessary as described in sections 8.3.6.1 or 8.3.6.2. If the testis negative and there are no further interferences suspected,adjust the pH to 12-13, refrigerate,
42、 and ship or transport to thelaboratory.8.3.6.1 If the sample contains sulfide as indicated with alead acetate test strip or is known to contain sulfides that willinterfere with the test method, dilute the sample with reagentwater until the lead acetate test strip no longer indicates thepresence of
43、sulfide (1500 mg/L Carbonate, Sulfide above 50 mg/L unless mitigated asdescribed in D6888-04.D7365077used, it should be tested to ensure that cyanide results are notaffected adversely. WarningWhen NaBH4is added tosamples that contain arsenic, the formation of toxic arsine gascan occur.8.3.12 Particu
44、late CyanideTo avoid low recoveries ofparticulate cyanide (for example, ferric ferrocyanide), allsamples should be held at room temperature at pH 12 for aminimum of 4 h prior to analysis.8.4 After the sample has been collected, treated for inter-ferences, and preserved with sodium hydroxide, refrige
45、rate thesample, then transport to the laboratory. Refer to Guide D 4840for chain-of-custody procedures.8.5 Upon receipt of sample(s) at the laboratory, verify thatthe sample is stabilized at the proper pH and that interferencesare not present as indicated in this practice. At a minimum, testunknown
46、samples for pH, sulfides, and oxidants using pHpaper, lead acetate test strips previously moistened with acetatebuffer, and KI starch paper, respectively. Document and miti-gate any interference discovered in the laboratory, and ifpossible, recollect the sample to mitigate the interference attime of
47、 collection. If resampling is not possible, qualify theresult as necessary.9. Keywords9.1 available cyanide; cyanide; free cyanide; hydrogen cya-nide; interference; preservative; sample collection; totalcyanideASTM International takes no position respecting the validity of any patent rights asserted
48、 in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the
49、 responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard
