ASTM D3557-2012 Standard Test Methods for Cadmium in Water《水中镉的标准试验方法》.pdf

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1、Designation: D3557 02 (Reapproved 2007)1D3557 12Standard Test Methods forCadmium in Water1This standard is issued under the fixed designation D3557; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe

2、r in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1 NOTEEditorial changes were made throughout in September 2007.1. Scope Scope*1.1 These test methods cover the determination of dissolved and total reco

3、verable cadmium in water and wastewater byatomic-absorption spectrophotometry and differential pulse anodic stripping voltammetry.2 Four test methods are included asfollows:ConcentrationRange SectionsTest Method AAtomic Absorption,Direct0.05 to 2.0mg/L7 to 15Test Method BAtomic Absorption,Chelation-

4、Extraction5 to 200 g/L 16 to 24Test Method CDifferential PulseAnodic Stripping Voltammetry1 to 100 g/L 25 to 34Test Method DAtomic Absorption,Graphite Furnace2 to 10 g/L 35 to 431.2 Test Method B can be used to determine cadmium in brines. It is the users responsibility to ensure the validity of the

5、se testmethods for waters of untested matrices.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem are mathematical conversions and may not be exact equivalents; therefore, each system shall be used independently of

6、theother.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Refer

7、enced Documents2.1 ASTM Standards:3D858 Test Methods for Manganese in WaterD1066 Practice for Sampling SteamD1068 Test Methods for Iron in WaterD1129 Terminology Relating to WaterD1192 Guide for Equipment for Sampling Water and Steam in Closed Conduits (Withdrawn 2003)4D1193 Specification for Reagen

8、t WaterD1687 Test Methods for Chromium in WaterD1688 Test Methods for Copper in WaterD1691 Test Methods for Zinc in WaterD1886 Test Methods for Nickel in WaterD2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water

9、 from Closed Conduits1 These test methods are under the jurisdiction of ASTM Committee D19 on Water and are the direct responsibility of Subcommittee D19.05 on Inorganic Constituentsin Water.Current edition approved Aug. 1, 2007Sept. 1, 2012. Published September 2007 September 2012. Originally appro

10、ved in 1977. Last previous edition approved in 20022007as D3557 02.D3557 02(2007)E01. DOI: 10.1520/D3557-02R07E01.10.1520/D3557-12.2 Platte, J. A., and Marcy, V. M., “A New Tool for the Water Chemist,” Industrial Water Engineering, May 1965.3 For referencedASTM standards, visit theASTM website, www.

11、astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what

12、 changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the

13、official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D3558 Test Methods for Cobalt in WaterD3559 Test Methods for Lead in WaterD3919 Practice for Measuring

14、Trace Elements in Water by Graphite Furnace Atomic Absorption SpectrophotometryD4841 Practice for Estimation of Holding Time for Water Samples Containing Organic and Inorganic ConstituentsD5810 Guide for Spiking into Aqueous SamplesD5847 Practice for Writing Quality Control Specifications for Standa

15、rd Test Methods for Water Analysis3. Terminology3.1 Definitions: For definitions of terms used in these test methods, refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 spiking solutionsolution, nthe standard solution added to the polarographic cell that is used to q

16、uantitate the sample.3.2.2 stripping peak potentialpotential, nthe applied potential versus SCE at which the stripping peak current is amaximum.3.2.3 SCESCE, nsaturated calomel electrode.3.2.4 stripping peak signalsignal, nthe current measured at the stripping peak maximum for a metal.4. Significanc

17、e and Use4.1 The test for cadmium is necessary because it is a toxicant and because there is a limit specified for cadmium in potable waterin the National Interim Primary Drinking Water Regulations. This test serves to determine whether the cadmium content of potablewater is above or below the accep

18、table limit.5. Purity of Reagents5.1 Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conformto the specifications of the Committee on Analytical Reagents of the American Chemical Society.4 Other grades may be used,provided it is

19、first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of thedetermination.5.2 Unless otherwise indicated, references to water shall be understood to mean reagent water conforming to SpecificationD1193, Type I. Other reagent water types may

20、 be used, provided it is first ascertained that the water is of sufficiently high purityto permit its use without adversely affecting the bias and precision of the test method. Type II water was specified at the time ofround-robin testing of this test method.6. Sampling6.1 Collect the samples in acc

21、ordance with the applicableASTM standard as follows: Practices D3370, Practice and D1066, andSpecification D1192.6.2 Samples shall be preserved with HNO3 (sp gr 1.42) to a pH of 2 or less immediately at the time of collection, normally about2 mL/L of HNO3. If only dissolved cadmium is to be determin

22、ed, the sample shall be filtered through a 0.45-m (No. 325)membrane filter before acidification. The holding time for samples may be calculated in accordance with Practice D4841.NOTE 1Alternatively, the pH may be adjusted in the laboratory if the sample is returned within 14 days. This could reduce

23、hazards of working withacids in the field when appropriate.TEST METHOD AATOMIC ABSORPTION, DIRECT7. Scope7.1 This test method covers the determination of dissolved and total recoverable cadmium in most waters and wastewaters.7.2 This test method is applicable in the range from 0.05 to 2.0 mg/Lof cad

24、mium. The range may be extended to concentrationsgreater than 2.0 mg/L by dilution of the sample.7.3 This test method has been used successfully with reagent grade water, river water, wastewater, ground water, tap water, lakewater, and refinery effluent. The information on precision and bias may not

25、 apply to other water. It is the users responsibility toensure the validity of this test method for waters of other matrices.8. Summary of Test Method8.1 Cadmium is determined by atomic absorption spectrophotometry. Dissolved cadmium is determined by aspirating a portionof the filtered sample direct

26、ly with no pretreatment. Total recoverable cadmium is determined by aspirating the sample following4 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For Suggestions on the testing of reagents not listed bythe American Chemical Society, see Annu

27、al Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D3557 122hydrochloric-nitric acid digestion and filtration. The same digestion procedure may be used to determine

28、total recoverable nickel(Test Methods D1886), chromium (Test Methods D1687), cobalt (Test Methods D3558), copper (Test Methods D1688), iron (TestMethods D1068), lead (Test Methods D3559), manganese (Test Methods D858), and zinc (Test Methods D1691).9. Interferences9.1 Calcium concentrations above 10

29、00 mg/L suppress the cadmium absorption. At 2000 mg/L of calcium the suppression is19 %.9.2 Sodium, potassium, sulfate, and chloride (9000 mg/Leach), magnesium (4500 mg/L), iron (4000 mg/L), nitrate (100 mg/L),and nickel, lead, copper, zinc, cobalt, and chromium (10 mg/L each), do not interfere.9.3

30、Background correction or a chelation-extraction procedure (see Test Method B) may be necessary to determine low levelsof cadmium in some waters.NOTE 2Instrument manufacturers instructions for use of the specific correction technique should be followed.10. Apparatus10.1 Atomic Absorption Spectrophoto

31、meter , for use at 228.8 nm.NOTE 3The manufacturers instructions shall be followed for all instrumental parameters. A wavelength other than 228.8 nm may be used if it hasbeen determined to be equally suitable.10.2 Cadmium Light SourceEither cadmium hollow-cathode lamps or multielement hollow-cathode

32、 lamps, or electrodeless-discharge lamps.10.3 Pressure-Reducing ValvesThe supplies of fuel and oxidant shall be maintained at pressures somewhat higher than thecontrolled operating pressure of the instrument by suitable valves.11. Reagents and Materials11.1 Cadmium Solution, Stock (1 mL = 1.0 mg Cd)

33、Dissolve 1.000 g of cadmium metal in a minimum quantity of HNO3 (spgr 1.42) and dilute to 1 L. A purchased cadmium stock solution of appropriate known purity is also acceptable.11.2 Cadmium Solution, Standard (1 mL = 0.1 mg Cd)Dilute 100.0 mL of the cadmium stock solution and 1 mL of HNO3(sp gr 1.42

34、) to 1000 mL with water.11.3 Hydrochloric Acid (sp gr 1.19)Concentrated hydrochloric acid (HCl).NOTE 4If the reagent blank concentration is greater than the method detection limit, distill the HCl or use spectrograde acid. (WarningWhen HClis distilled, an azeotropic mixture is obtained (approximatel

35、y 6 N HCl). Therefore, whenever concentrated HCl is specified for the preparation of a reagentor in the procedure, use double the volume specified if distilled acid is used.)11.4 Nitric Acid (sp gr 1.42)Concentrated nitric acid (HNO3).NOTE 5If the reagent blank concentration is greater than the meth

36、od detection limit, distill the HNO3 or use a spectrograde acid.11.5 Nitric Acid (1 + 499)Add 1 volume of HNO3 (sp gr 1.42) to 499 volumes of water.11.6 Oxidant:11.6.1 Air, which has been passed through a suitable filter to remove oil, water, and other foreign substances is the usual oxidant.11.7 Fu

37、el:11.7.1 AcetyleneStandard, commercially available acetylene is the usual fuel.Acetone, always present in acetylene cylinders,can affect analytical results. The cylinder should be replaced at 50 psig (345 kPa).345 kPa (50 psi). (Warning “Purified” gradeacetylene containing a special proprietary sol

38、vent rather than acetone should not be used with poly(vinyl chloride) tubing asweakening of the tubing walls can cause a potentially hazardous situation.)12. Standardization12.1 Prepare 100 mL each of a blank and at least four standard solutions to bracket the expected cadmium concentration rangeof

39、the samples to be analyzed by diluting the standard cadmium solution (11.2) with HNO3 (1 + 499). Prepare the standards eachtime the test is to be performed.12.2 When determining total recoverable cadmium, add 0.5 mL of HNO3 (sp gr 1.42) to each blank and standard solution andproceed as directed in 1

40、3.2 through 13.4.After the digestion of the blank and standard solutions has been completed in 13.4, returnto 12.3 to complete the standardization for total recoverable determinations. When determining dissolved cadmium, proceed with12.3.12.3 Aspirate the blank and standards and record the instrumen

41、t readings. Aspirate HNO3 (1 + 499) between each standard.12.4 Prepare an analytical curve by plotting the absorbance versus the concentration for each standard on the instrumentsoftware. Alternatively, read directly in concentration if this capability is provided with the instrument.D3557 12313. Pr

42、ocedure13.1 Measure 100.0 mL of a well-mixed acidified sample into a 125-mL beaker or flask.NOTE 6If only dissolved cadmium is to be determined, start with 13.5.13.2 Add 5 mL of HCl (sp gr 1.19) to each sample.13.3 Heat the samples on a steam bath or hotplate in a well-ventilated hood until the volu

43、me has been reduced to 15 to 20 mL,making certain that the samples do not boil.NOTE 7For samples containing appreciable amounts of suspended matter or dissolved solids, the amount of reduction in volume is left to thediscretion of the analyst.NOTE 8Many laboratories have found block digestion system

44、s a useful way to digest samples for trace metals analysis. Systems typically consist ofeither a metal or graphite block with wells to hold digestion tubes. The block temperature controller must be able to maintain uniformity of temperatureacross all positions of the block. For trace metals analysis

45、, the digestion tubes should be constructed of polypropylene and have a volume accuracy ofat least 0.5%. All lots of tubes should come with a certificate of analysis to demonstrate suitability for their intended purpose.13.4 Cool and filter the samples through a suitable filter such as fine-textured

46、, acid-washed, ashless, paper into 100-mLvolumetric flasks. Wash the filter paper two or three times with water and adjust to volume.13.5 Aspirate each filtered and acidified sample and determine its absorbance or concentration at 228.8 nm. Aspirate HNO3(1 + 499) between each sample.14. Calculation1

47、4.1 Calculate the concentration of cadmium in the sample, in milligrams per litre, using the analytical curve prepared in 12.4.15. Precision and Bias515.1 The precision of this test method was tested by 17 laboratories in reagent water, river water, wastewater, ground water, tapwater, lake water, an

48、d refinery effluent. The overall bias and precision of this test method, within its designated range, varies withthe quantity being measured in accordance with Table 1.15.2 These data may not apply to waters of the matrices, therefore, it is the responsibility of the analyst to ensure the validityof

49、 the test method in other matrices.15.3 Precision and bias for this test method conforms to Practice D2777 77, which was in place at the time of collaborativetesting. Under the allowances made in 1.4 of Practice D2777 06, 08, these precision and bias data meet existing requirementsfor interlaboratory studies of Committee D19 test methods.TEST METHOD BATOMIC ABSORPTION, CHELATION-EXTRACTION16. Scope16.1 This test method covers the determination of dissolved and total recoverable cadmium in most waters and brines.16.2 This test me