1、Designation: D 7365 09Standard 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 () 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 anal
3、ysis 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 recomme
4、ndedfor 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 example
5、,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 standard
6、 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 Practice
7、s 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 Holding
9、 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 Separati
10、on 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 with
11、 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 A
12、naly-sis, In-Line Ultraviolet Digestion and Amperometric De-tection2.2 U.S. EPA Methods:3EPA OIA-1677EPA Method 335.2EPA Method 335.42.3 APHA Standard:4Standard Methods 4500-CN Methods C, D, E, F, G, and I2.4 USGS Methods:5USGS I-3300-851This practice is under the jurisdiction of ASTM Committee D19
13、on Water andis the direct responsibility of Subcommittee D19.06 on Methods for Analysis forOrganic Substances in Water.Current edition approved Feb. 15, 2009. Published March 2009. Originallyapproved in 2007. Last previous edition approved in 2007 as D 7365 07.2For referenced ASTM standards, visit t
14、he 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 Environmental Protection Agency (EPA), ArielRios Bldg., 1200 Pennsylva
15、nia Ave., NW, Washington, DC 20460, http:/www.epa.gov.4Standard Methods for the Examination of Water and Wastewater, 21st edition(2005),American Public HealthAssociation (APHA), 800 I Street, NWWashington,DC 20001, www.apha.org.5Available from United States Geological Survey, 12201 Sunrise Valley Dr
16、ive,Reston, VA, 20192, www.usgs.gov.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.USGS I-4302-853. Terminology3.1 Definitions:For definitions of terms used in this practice, refer toTerminology D 1129 and Guide D 6696.3.2 In this p
17、ractice, refrigeration shall designate storing thesample between its freezing point and 6C.4. Summary of Practice4.1 Samples are collected in appropriate containers andmitigated for known interferences either in the field duringsample collection or in the laboratory prior to analysis.5. Significance
18、 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 vio-lations or undetected cyanide releases into the
19、 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 Reagents of the American ChemicalSociety, where such specif
20、ications 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, referencesto water shall be understood to mean reagent
21、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, approximately 500mL.6.4 Lead Acetate Test StripsTurns black
22、 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 alternative test stripsmay be used if they are shown
23、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 one test strip may be necessary to cover thisrange.6.7 Sodium Hydroxide Solution (0.1 M)Ina1Lvolumet-ric flask,
24、 dissolve 4 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 transfer to a 100-mL volumetric flask anddilute to volume. WarningThis is an exothermic reactionand the solution w
25、ill 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 (EDA)6.11 Reducing AgentsAscorbic acid, sodium arsenite(NaAsO2).6.12 Filter Paper or Syringe equipped with Leur-LockFiltersUnless specified, 0.
26、45 m pore size.6.13 Acidification ReagentsConcentrated hydrochloricacid (HCl) or concentrated sulfuric acid (H2SO4).6.14 Sample BottlesSee Section 8.2 for further informa-tion about sample bottles.7. Hazards7.1 WarningBecause of the toxicity of cyanide, greatcare must be exercised in its handling. A
27、cidification of cyanidesolutions produces toxic hydrocyanic acid (HCN). Adequateventilation is necessary when handling cyanide solutions and afume hood should be utilized whenever possible.7.2 WarningMany of the reagents used in these testmethods are highly toxic. These reagents and their solutionsm
28、ust 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 streams refer to PracticeD 3370. When sampling fluvial sediment in motion or openchannel flow refer to Guide D 4411.
29、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 analyticalmethods used to measure the cyanide.8.2 Sample Containers:8.2.1 Sample containers shall be made of materi
30、als that willnot contaminate the sample, cleaned thoroughly to remove allextraneous surface contamination prior to use. Chemicallyresistant glass containers as well as rigid plastic containersmade of high density polyethylene (HDPE) are suitable.Samples should be collected and stored in amber gas ti
31、ght vialsor narrow mouth bottles to minimize exposure to ultravioletradiation and to minimize headspace in the sample containers(for example, amber open top VOA vials, amber Boston roundbottles, or amber narrow-mouth HDPE bottles).8.2.2 Virgin commercially-cleaned containers certified to befree of c
32、ontamination 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:8.3.1 Collect a sample volume that is s
33、ufficient to theanalytical method into a sample bottle described above. If therequired sample volume is not specified, usually 1 L issufficient for most analytical test methods, however, flow6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For S
34、uggestions 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 Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D7365092injection and auto
35、mated methods usually consume consider-ably less sample volume than manual methods.8.3.2 Unless otherwise specified, samples must be analyzedwithin 14 days; however, it is recommended to estimate theactual holding time for each sample matrix as described inPractice D 4841. Certain sample matrices ma
36、y require imme-diate analysis to avoid cyanide degradation due to interfer-ences. A holding time study is required if there is evidence thatcyanide degradation occurs from interferences which wouldcause the holding time to be less than specified in this practice.Potential interferences and their cor
37、responding analyticalmethods are shown in Table 1.8.3.3 In the absence of interference, simple cyanides such asHCN, KCN, and NaCN are determined readily by each of thedeterminative steps, however, to determine “total” cyanide,metal cyanide bonds must be broken and cyanide separated toproduce simple
38、cyanide. In most total cyanide methods, this isaccomplished by distillation from acid solution. Althoughdistillation is assumed to eliminate or at least minimize mostinterferences, the high temperature and strong acid solutionscan potentially introduce significant positive or negative bias.Interfere
39、nces for total cyanide by distillation are listed inTables 2 and 3. Interferences are also dependent on thedeterminative step, which are shown in Table 4.8.3.4 There may be interferences that are not mitigated bythis procedure. Any removal or suppression of interferencemay be employed, provided the
40、laboratory demonstrates that itmore accurately measures cyanide through quality controlmeasures described in the analytical test method. Any removalor suppression technique not described in this practice or theanalytical test method should be documented along withsupporting data. A challenge solutio
41、n with potential interfer-ences for cyanide analysis is described in X1.1.1, which can beused as a sample matrix to examine analytical method perfor-mance.8.3.5 Treat the sample immediately upon sample collectionusing any or all of the following techniques as necessary,followed by refrigeration. If
42、applicable, laboratory mitigationtechniques are also specified.NOTE 1Historically, sodium hydroxide has been added to preservewater samples for cyanide analysis during sample collection; however,this can result in rapid cyanide degradation or cyanide formation duringsample storage. Therefore, sodium
43、 hydroxide should not be added as apreservative unless it is necessary to raise the pH for safety reasons (forexample, process samples). If sodium hydroxide preservation is deemednecessary, add sodium hydroxide solution described in Sections 6.7 or 6.8to pH 1011, being careful not to add excess. Aci
44、dic samples (pH 1 % suspended solids) or if the sample is known orsuspected to contain particulate cyanides (for example, ferricD7365093TABLE 1 Examples of Potential Interferences if not Mitigated in Standard Cyanide MethodsMethod Description Measurement Interferences NumberTotalCyanideAutomatedUVCo
45、lorimetric AldehydesColorFatty AcidsMercuryNitrateNitriteOxidantsSulfidesTurbiditySulfur CompoundsThiocyanateCFR Kelada-01D 4374TotalCyanideManualDistillationMgCl2Amperometric AldehydesCarbonatesNitriteNitrateOxidantsSulfideSulfur CompoundsThiocyanateD 7284D 2036 Test Method ATotalCyanideManualDisti
46、llationMgCl2Manual orAutomatedColorimetricAldehydesCarbonatesFatty AcidsNitrateNitriteOxidantsSugarsSulfideSulfur CompoundsThiocyanateColorTurbidityD 2036 Test Method AStandard Methods 4500-CN C/E,EPA 335.2,EPA 335.4TotalCyanideManualDistillationMgCl2ISE AldehydesCarbonatesFatty AcidsNitrateNitriteO
47、xidantsSulfideSulfur CompoundsThiocyanateColorTurbidityD 2036 Test Method A,Standard Methods 4500-CN C/FTotalCyanideManualDistillationMgCl2Titrimetric AldehydesCarbonatesFatty AcidsNitrateNitriteOxidantsSugarsSulfideSulfur CompoundsThiocyanateTurbidityD 2036 Test Method A,Standard Methods 4500-CN C/
48、DAvailableCyanideFlow InjectionLigand ExchangeAmperometric CarbonatesOxidantsSulfideD 6888,EPA OIA-1677CyanideAmenable toChlorinationAlkalineChlorination andManualDistillationsManualColorimetricAldehydesCarbonatesFatty AcidsNitrateNitriteOxidantsSulfideSulfur CompoundsThiocyanateColorTurbidityUnknow
49、ns that cause negative resultsD 2036 Test Method B,Standard Methods 4500-G/ED7365094TABLE 1 ContinuedMethod Description Measurement Interferences NumberWeak AcidDissociableCyanideBufferedDistillationManualColorimetricAldehydesCarbonatesFatty AcidsNitrateNitriteOxidantsSugarsSulfideSulfur CompoundsThiocyanateTurbidityD 2036 Test Method C,Standard Methods 4500-CN I/EWeak AcidDissociableCyanideAutomatedMethodAutomatedColorimetricAldehydesColorFatty AcidsMercuryNitrateNitriteOxidantsSulfidesTurbidityD 4374Weak AcidDissociableCyanideBufferedDistillationISE Aldehyd
