1、Designation: D 7365 09aStandard 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
2、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 practice is applicable for the collection and pres-ervation of water samples for the ana
3、lysis of cyanide. Thispractice addresses the mitigation of known interferences priorto the analysis of cyanide. Responsibilities of field samplingpersonnel and the laboratory are indicated.1.2 The sampling, preservation and mitigation of interfer-ence procedures described in this practice are recomm
4、endedfor the analysis of total cyanide, available cyanide, weak aciddissociable cyanide, and free cyanide by Test Methods D 2036,D 4282, D 4374, D 6888, D 6994, D 7237, D 7284, andD 7511. The information supplied in this practice can also beapplied to other analytical methods for cyanide, for exampl
5、e,EPA Method 335.4.1.3 The values stated in SI units are to be regarded asstandard. No other units 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 standar
6、d to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 2036 Test Methods for Cyanides in WaterD 3370 Practic
7、es for Sampling Water from Closed ConduitsD 3694 Practices for 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
8、 and Wastewater by MicrodiffusionD 4374 Test Methods for Cyanides 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 Holdin
9、g Time for WaterSamples Containing Organic and Inorganic ConstituentsD 5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisD 6888 Test Method for Available Cyanide with LigandDisplacement and Flow Injection Analysis (FIA) UtilizingGas Diffusion Separat
10、ion and Amperometric DetectionD 6994 Test Method for Determination of Metal CyanideComplexes in Wastewater, Surface Water, Groundwaterand Drinking Water Using Anion Exchange Chromatogra-phy with UV DetectionD 6696 Guide for Understanding Cyanide SpeciesD 7237 Test Method for Aquatic Free Cyanide wit
11、h FlowInjection Analysis (FIA) Utilizing Gas Diffusion Separa-tion and Amperometric DetectionD 7284 Test Method for Total Cyanide in Water by MicroDistillation followed by Flow Injection Analysis with GasDiffusion Separation and Amperometric DetectionD 7511 Total Cyanide by Segmented Flow Injection
12、Analy-sis, In-Line Ultraviolet Digestion and Amperometric De-tection2.2 U.S. EPA Methods:3EPA OIA-1677EPA Method 335.2EPA Method 335.42.3 USGS Methods:4USGS I-3300-85USGS I-4302-853. Terminology3.1 Definitions: For definitions of terms used in this prac-tice, refer to Terminology D 1129 and Guide D
13、6696.1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.06 on Methods for Analysis forOrganic Substances in Water.Current edition approved Oct. 1, 2009. Published October 2009. Originallyapproved in 2007. Last previous edition
14、approved in 2009 as D 7365 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.3Available from United States E
15、nvironmental Protection Agency (EPA), ArielRios Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20460, http:/www.epa.gov.4Available 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, We
16、st Conshohocken, PA 19428-2959, United States.3.1.1 refrigeration, nstoring the sample between its freez-ing point and 6C.3.1.2 holding time, nthe time lapsed from sample collec-tion to sample analysis.4. Summary of Practice4.1 Samples are collected in appropriate containers andmitigated for known i
17、nterferences either in the field duringsample collection or in the laboratory 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
18、ornegative bias potentially resulting in unnecessary permit 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
19、to the specifications of theCommittee on Analytical Reagents of the American ChemicalSociety, where such specifications are available.5Other gradesmay be used, provided it is first ascertained that the reagent isof sufficiently high purity to permit its use without lesseningthe accuracy of the deter
20、mination.6.2 Purity of WaterUnless otherwise indicated, referencesto 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. Ad
21、d glacialacetic acid to yield a solution pH of 4.5, approximately 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 Tes
22、t PaperTurns blue inpresence of free chlorine. Commercial alternative 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 2 to12. More than
23、one test strip may be necessary to cover thisrange.6.7 Sodium Hydroxide Solution (1 M)In a 1-L volumetricflask, dissolve 40 g NaOH in reagent water and dilute tovolume.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 tr
24、ansfer to a 100-mL volumetric flask anddilute to volume. 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 Ethylenediamine Solution (EDA), 3.5%Dilute 3.5m
25、L (or 3.15 g) of anhydrous NH2CH2NH2to 100 mL withwater.6.11 Reducing AgentsAscorbic acid, sodium arsenite(NaAsO2).6.12 Filter Paper or Syringe equipped with Leur-LockFilters5 m and 0.45 m pore size. If unspecified, use 0.45um pore size.6.13 Dilute Acetic AcidAdd 1 part glacial acetic acid to 9parts
26、 water.6.14 Lead Carbonate (PbCO3) or Lead Acetate(Pb(C2H3O2)23H2O, Lead acetate can be put in solution withwater at a suggested concentration of 50 g/L.6.15 Sulfamic acid (0.4N), H2NSO3HDissolve 40 gH2NSO3H in 1 liter of water.6.16 Sample BottlesSee Section 8.2 for further informa-tion about sample
27、 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 should be utilized whenever possible
28、.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 samplingclosed conduits such as process strea
29、ms 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, etc.,as these parameters may vary depending on the ana
30、lyticalmethods 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. Chemicallyresistant glass containers as well as rigid plastic contai
31、nersmade of high density polyethylene (HDPE) are suitable.Samples should be collected and stored in amber bottles tominimize exposure to ultraviolet radiation in the samplecontainers. If samples will only be tested for total cyanide,amber containers are not mandatory.8.2.2 Virgin commercially-cleane
32、d containers certified to befree of contamination are recommended; otherwise, washcontainers with soap or biodegradable detergent if required,then dry by draining. For further information on samplecontainers, see Practices D 3694.8.3 Sample Collection, Preservation, and Mitigation ofInterferences:5R
33、eagent 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, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
34、and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D 7365 09a28.3.1 Collect a sample volume that is sufficient to theanalytical method into a sample bottle described above. If therequired sample volume is not specified, usually 1 L issufficient for most analytical test
35、methods, however, flowinjection and automated methods usually consume consider-ably less sample volume than manual methods.8.3.2 Unless otherwise specified, samples must be analyzedwithin 14 days. Certain sample matrices may require a shorterholding time or immediate analysis to avoid cyanide degrad
36、a-tion due to interferences. Hold the sample no longer than thetime necessary to preclude a change in cyanide concentration.A holding time study described in Practice D 4841 is requiredif there is evidence that a change in cyanide occurs frominterferences which would cause the holding time to be sho
37、rterthan specified in this section, or within the time the samplewould be held if shorter than the time specified in this section.Potential interferences and their corresponding analyticalmethods are shown in Table 1.NOTE 1It is recommended to investigate holding times for samplesthat meet any of th
38、e following conditionsdisinfected by chloraminationor ultraviolet irradiation, ammonia present and chlorinated, sulfur dioxideor sulfite used to dechlorinate, or if aldehydes are known or suspected tobe present.8.3.3 In the absence of interference, simple cyanides such asHCN, KCN, and NaCN are deter
39、mined readily by each of thedeterminative steps, however, to determine “total” cyanide,metal cyanide bonds must be broken and cyanide separated toproduce simple cyanide. In most total cyanide methods, this isaccomplished by distillation from acid solution. Althoughdistillation is assumed to eliminat
40、e or at least minimize mostinterferences, the high temperature and strong acid solutionscan potentially introduce significant positive or negative bias.Interferences for total cyanide by distillation are listed inTables 2 and 3. Interferences are also dependent on thedeterminative step, which are sh
41、own in Table 4.8.3.4 There may be interferences that are not mitigated bythis procedure. Any technique for removal or suppression ofinterference may be employed, provided the laboratory dem-onstrates that it more accurately measures cyanide throughquality control measures described in the analytical
42、 testmethod. Any removal or suppression technique not describedin this practice or the analytical test method should bedocumented along with supporting data. A challenge solutionwith potential interferences for cyanide analysis is described inX1.1.1, which can be used as a sample matrix to examinean
43、alytical method performance.8.3.5 Treat the sample immediately upon sample collectionusing any or all of the following techniques as necessary,followed by adjustment of the sample to pH 10 andrefrigeration. If applicable, laboratory mitigation techniquesare also specified. Preserve the sample immedi
44、ately (within 15minutes of collection or treatment using procedures describedin this practice) by adding 1 mL of 1M NaOH (Section 6.7) perliter of sample, and then verify that the pH is greater than pH10 with indicator test strips (Section 6.6). If necessary, con-tinue to add sodium hydroxide (Secti
45、on 6.7 or 6.8) drop wiseuntil the pH is greater than pH 10 being careful not to addexcess. Do not add NaOH if the cyanide concentration wouldchange as a result of the addition.8.3.5.1 Adding NaOH to samples containing formaldehyde(see Note 2 in Section 8.3.8) can possibly increase the cyanideconcent
46、ration during storage. Conversely, adding NaOH tosamples containing sulfite (see Note 3 in Section 8.4.2.2) canrapidly decrease the cyanide concentration. If the addition orlack of addition of NaOH would affect the holding time, holdthe sample for a time no longer than the time necessary tomaintain
47、sample integrity (Section 8.3.2).8.3.6 SulfideDuring sample collection, test for the pres-ence of sulfide by placing a drop of sample on a lead acetatetest strip that has been previously moistened with acetatebuffer. If the test strip turns black, sulfide is present (aboveapproximately 50 mg/L S2-)
48、and treatment is necessary asdescribed below.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 thepresenc
49、e of sulfide (1 % suspended solids) or if the sample is known orsuspected to contain particulate cyanides (for example, ferricferro cyanide or Prussian blue), save the solids for extraction asdescribed in Section 8.4.3 on particulate cyanides, otherwise,discard the solids and filter.8.3.8 AldehydesIf formaldehyde, acetaldehyde, or otherwater-soluble aldehydes are known or suspected to be present,treat the sample with 2 mL 3.5 % ethylenediamine (Section6.10) per 100 mL of sample to avoid the formation ofcyanohydrins. It has been found that this quantity
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