1、Designation: D 3866 07Standard Test Methods forSilver in Water1This standard is issued under the fixed designation D 3866; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates
2、 the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the atomic absorption deter-mination of silver in water. Three test methods are given asfollows:ConcentrationRange SectionsTest Method AAtom
3、ic Absorp-tionChelation-ExtractionA1to10g/L 7to15Test Method BAtomic Absorp-tionDirect0.1to10mg/L 16to24Test Method CAtomic Absorp-tionGraphite Furnace1to25g/L 25to33ASimilar to that in Brown, E., Skougstad, M. W., and Fishman, M. J., “Methodsfor Collection and Analysis of Water Samples for Dissolve
4、d Minerals and Gases,”Techniques of Water-Resources Investigations of the U.S. Geological Survey,Book 5, Chapter A1, 1970, p. 46.1.2 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
5、 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in Note 3, Note 5, Note 9, andNote 13.2. Referenced Documents2.1 ASTM Standards:2D 1129 Terminology Relating to WaterD 1193 Specification fo
6、r Reagent WaterD 2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD 3370 Practices for Sampling Water from Closed ConduitsD 3919 Practice for Measuring Trace Elements in Water byGraphite Furnace Atomic Absorption SpectrophotometryD 4691 Practic
7、e for Measuring Elements in Water by FlameAtomic Absorption SpectrophotometryD 4841 Practice for Estimation of Holding Time for WaterSamples Containing Organic and Inorganic ConstituentsD 5810 Guide for Spiking into Aqueous SamplesD 5847 Practice for Writing Quality Control Specificationsfor Standar
8、d Test Methods for Water Analysis3. Terminology3.1 Definition of Term Specific to These Test Methods:3.1.1 laboratory control sample, na solution with a cer-tified concentration of silver.3.1.2 total recoverable silveran arbitrary analytical termrelating to forms of silver that are determinable by t
9、hedigestion method that is included in the procedures.3.2 DefinitionsFor definition of terms used in these testmethods, refer to Terminology D 1129.4. Significance and Use4.1 The principal adverse effect of silver in the body iscosmetic. It causes argyria, a permanent, blue-gray discolora-tion of th
10、e skin, eyes, and mucous membranes.4.2 Relatively small quantities of silver are bactericidal orbacteriostatic and find limited use in both disinfection ofswimming pool waters and point-of-use water filters.5. Purity of Reagents5.1 Reagent grade chemicals shall be used in all tests.Unless otherwise
11、indicated, it is intended that all reagents shallconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society, when suchspecifications are available.3Other grades may be used, pro-vided it is first ascertained that the reagent is of sufficientlyhigh purity to
12、 permit its use without lessening the accuracy ofthe determination.5.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Specification D 1193, Type I, II, or III water. Type I ispreferred and more commonly used. Other reagent water t
13、ypesmay be used provided it is first ascertained that the water is of1These test methods are under the jurisdiction of ASTM Committee D19 onWater and are the direct responsibility of Subcommittee D19.05 on InorganicConstituents in Water.Current edition approved Aug. 1, 2007. Published August 2007. O
14、riginallyapproved in 1979. Last previous edition approved in 2002 as D 3866 02.2For 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 o
15、nthe ASTM website.3Reagent Chemicals, 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
16、 States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.sufficiently high purity to permit its use without adverselyaffecting the precision
17、and bias of the test method. Type IIwater was specified at the time of round robin testing of thesetest methods.NOTE 1The user must ensure the type of reagent water chosen issufficiently free of interferences. The water should be analyzed using thetest method.6. Sampling6.1 Collect the sample in acc
18、ordance with Practices D 3370.The holding time for the samples may be calculated inaccordance with Practice D 4841.6.2 Preserve samples for Test Method A with HNO3(sp gr1.42) to a pH of 2 or less immediately at the time of collection;normally about 2 mL/L is required. If only dissolved silver isto b
19、e determined, filter the sample at time of collection througha 0.45-m membrane filter before acidification.6.3 Do not preserve samples for Test Methods B and C atthe time of collection. If only dissolved silver is to bedetermined, filter the sample through a 0.45-m membranefilter at time of collecti
20、on.Add cyanogen iodide (CNI) solutionto the samples in the laboratory prior to analysis. For totalrecoverable silver it is preferable to add the cyanogen iodide tothe entire sample to avoid a nonhomogeneous solution; there-fore, it is advisable to collect a discrete sample for silver.TEST METHOD AAT
21、OMIC ABSORPTIONCHELATION EXTRACTION7. Scope7.1 This test method4covers the determination of dissolvedand total recoverable silver in most water and wastewaters.7.2 This test method is applicable in the range from 1 to 10g/L of silver. The range may be extended by dilution of theoriginal sample.7.3 T
22、his test method has been used successfully withreagent water, natural surface water, and drinking water. Theinformation on precision and bias may not apply to otherwaters. It is the users responsibility to ensure the validity ofthis test method for waters of untested matrices.8. Summary of Test Meth
23、od8.1 Silver is determined by atomic absorption spectrometry.The element, either dissolved or total recoverable, is chelatedwith ammonium pyrrolidine dithiocarbamate (APDC) andextracted with methyl isobutyl ketone (MIBK). The extract isaspirated into an air-acetylene flame of the spectrophotometer.T
24、otal recoverable silver is determined following nitric aciddigestion and filtration.9. Interferences9.1 Concentrations of iron greater than 25 mg/L interfere bysuppressing the silver absorption.10. Apparatus10.1 Atomic Absorption Spectrophotometer for use at 328.1nm. A general guide for the use of f
25、lame atomic absorptionapplications is given in Practice D 4691.NOTE 2The manufacturers instructions should be followed for in-strumental parameters. Wave-lengths other than 328.1 nm may be used ifthey have been determined to be equally suitable.10.2 Silver Hollow-Cathode Lamp.10.3 Pressure-Reducing
26、ValvesThe supplies of fuel andoxidant shall be maintained at pressures somewhat higher thanthe controlled operating pressure of the instrument by suitablepressure-reducing valves.11. Reagents and Materials11.1 Ammonium Pyrrolidine Dithiocarbamate (APDC) So-lution (1 g/100 mL)Dissolve 1.0 g of APDC i
27、n 100 mL ofwater. Prepare fresh before each use.11.2 Bromophenol Blue Indicator Solution (0.1 g/100mL)Dissolve 0.1 g of bromophenol blue in 100 mL of 50 %ethanol or isopropanol.11.3 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).11.4 Hydrochloric Acid (1 + 49)Add 1 volume of hyd
28、ro-chloric acid (HCl, sp gr 1.19) to 49 volumes of water.11.5 Methyl Isobutyl Ketone (MIBK).NOTE 3Warning: Avoid inhalation and conduct all manipulation in awell-ventilated hood.11.6 Nitric Acid (sp gr 1.42)Concentrated nitric acid(HNO3).NOTE 4If a high reagent blank is obtained, distill the HNO3or
29、use aspectrograde acid.11.7 Silver Solution, Stock (1.0 mL = 100 g Ag)Crushapproximately2gofsilver nitrate (AgNO3) crystals and dry toconstant mass at 40C. Dissolve 0.1575 g of AgNO3in watercontaining 5 mL of concentrated HNO3and dilute to 1000 mL.Store in an amber glass bottle.11.8 Silver Solution,
30、 Intermediate (1.0 mL = 1.00 g Ag)Dilute 10.0 mL of silver stock solution and 5 mL of concen-trated HNO3to 1000 mL with water. Store in an amber glassbottle. A purchased stock solution of adequate purity is alsoacceptable.11.9 Silver Solution, Standard (1.0 mL = 0.100 g Ag)Dilute 100 mL of silver in
31、termediate solution and 5 mL ofconcentrated HNO3to 1000 mL with water. Prepare freshbefore use.11.10 Sodium Hydroxide Solution (100 g/L)Dissolve 100g of NaOH in water and dilute to 1000 mL.11.11 Oxidant:11.11.1 Air, that has been passed through a suitable filter toremove oil, water, and other foreig
32、n substances is the usualoxidant.11.12 Fuel:11.12.1 Acetylene-Standard, commercially available acety-lene is the usual fuel. Acetone, always present in acetylenecylinders, can affect analytical results. The cylinder should bereplaced at 50 psig (345 kPa). (Warning, see Note 5.)4Similar to that in Br
33、own, E., Skougstad, M. W., and Fishman, M. J., “Methodsfor Collection and Analysis of Water Samples for Dissolved Minerals and Gases,”Techniques of Water - Resources Investigations of the U.S. Geological Survey, Book5, Chapter A1, 1970, p. 46.D 3866 072NOTE 5Warning: “Purified” grade acetylene conta
34、ining a specialproprietary solvent rather than acetone must not be used with poly(vinylchloride) tubing as weakening of the tubing walls causes a potentiallyhazardous situation.12. Standardization12.1 Prepare a blank and sufficient standards containingfrom 0.0 to 1.0 g of silver by diluting 0.0 to 1
35、0.0-mL portionsof silver standard solution to approximately 100 mL.12.2 To determine total recoverable silver, use 125-mLbeakers or flasks, add 5.0 mL of HNO3(sp gr 1.42), andproceed as directed in 13.3 through 13.10. To determinedissolved silver use 200-mL volumetric flasks and proceed asdirected i
36、n 13.5 through 13.10. Treat the blank and eachstandard in the same manner as the samples.12.3 Construct an analytical curve by plotting the absor-bances of standards versus micrograms of silver. Alternatively,read directly in concentration if this capability is provided withthe instrument.13. Proced
37、ure13.1 Measure a volume of a well-mixed acidified samplecontaining less than 1.0 g of silver (100-mL maximum) intoa 125-mLbeaker or flask and adjust the volume to 100 mLwithwater.NOTE 6If only dissolved silver is to be determined, measure a volumeof filtered and acidified sample containing less tha
38、n 1.0 g of silver (100mL maximum) into a 200-mL volumetric flask and adjust the volume to100 mL and start with 13.5.13.2 Add 5 mL of HNO3(sp gr 1.42) to each sample.13.3 Heat the samples on a steam bath or hot plate in awell-ventilated hood until the volume has been reduced to 15to 20 mL making cert
39、ain that the samples do not boil.NOTE 7For brines and samples with a high concentration of sus-pended matter, the amount of reduction in volume is left to the discretionof the analyst.13.4 Cool and filter each sample through a filter (such as afine-textured acid washed, ashless paper) into a 200-mLv
40、olumetric flask. Wash the filter paper two or three times withwater and adjust the filtrate to about 100 mL.13.5 Add 2 drops of bromophenol blue indicator solutionand mix.13.6 Adjust the pH by addition of NaOH solution (100 g/L)until a blue color persists. Add HCl (1 + 49) by drops until theblue col
41、or just disappears; then add 2.5 mL of HCl (1 + 49) inexcess. The pH at this point should be 2.3.NOTE 8The pH adjustment in 13.6 may be made with a pH meterinstead of using indicator.13.7 Add 2.5 mL ofAPDC solution and mix. The pH shouldbe approximately 2.8.13.8 Add 10.0 mLof MIBK and shake vigorous
42、ly for 1 min.NOTE 9Warning: Perform in a well ventilated hood (see Note 3).13.9 Allow the layers to separate and add, carefully downthe side of the flask, water until the ketone layer is completelyin the neck of the flask.NOTE 10MIBK is soluble to some extent in water; therefore avoidany undue agita
43、tion of the solution during and after addition of waterwhich could result in a concentration of the metal chelate in the MIBKlayer. To avoid this problem, MIBK-saturated water may be used to raisethe MIBK layer into the neck of the flask.13.10 Atomize the ketone layer and record the scale readingor
44、concentration (Note 11). Aspirate water-saturated MIBKbetween each sample.NOTE 11It is necessary to reduce the acetylene flow when aspiratingan organic solvent (MIBK) to obtain a nonluminous flame. Also allow theflame conditions to come to equilibrium before aspirating samples.14. Calculation14.1 De
45、termine the weight of silver in each sample byreferring to 12.3. Calculate the concentration of silver inmicrograms per litre as follows:Silver, g/L 5 1000/A! 3 Bwhere:A = volume of original sample, mL, andB = weight of silver in sample, g.15. Precision and Bias515.1 The single-operator and overall
46、precision of this testmethod within its designated range for four laboratories, whichinclude a total of seven operators analyzing each sample onthree different days varies with the quantity being tested, seeTable 1.15.2 Recoveries of known amounts of silver (from silvernitrate) in a series of prepar
47、ed standards for the same labora-tories and operators are shown in Table 1.15.3 The collaborative test data were obtained on reagentwater, natural surface water, and drinking water. This data maynot apply to untested matrices. It is the users responsibility toensure the validity of this test method
48、for waters of untestedmatrices.15.4 Precision and bias for this test method conforms toPractice D 2777-77, which was in place at the time ofcollaborative testing. Under the allowances made in 1.4 of D2777-06, these precision and bias data do meet existingrequirements for interlaboratory studies of C
49、ommittee D19 testmethods.5Supporting data are available from ASTM Headquarters. Request RR: D-19-1062.TABLE 1 Determination of Bias and Precision for Test Method AAmountAdded,g/LAgAmountFound,g/LAgBias,%StatisticallySignificant,95 %ConfidenceLevelOverallPrecision,StDegrees ofFreedomReagent Water, Type II2.0 2.18 + 9.0 no 0.77 75.0 5.15 + 3.0 no 1.34 78.0 8.08 + 1.0 no 1.86 7Natural Water of Choice2.0 2.37 + 18.5 yes 0.74 75.0 4.99 0.2 no 0.92 78.0 8.38 + 4.8 no 2.21 7D 3866 073TEST METHOD BATOMIC ABSORPTIONDIRECT16. Scope16.1
