ASTM E396-2012e1 6250 Standard Test Methods for Chemical Analysis of Cadmium《镉化学分析的标准试验方法》.pdf

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1、Designation: E396 121Standard Test Methods forChemical Analysis of Cadmium1This standard is issued under the fixed designation E396; 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

2、 indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEEditorial corrections were made throughout in August 2012.1. Scope1.1 These test methods cover the chemical analysis ofcadmium having chemical compositions with th

3、e followinglimits:Element Composition, max, %Antimony 0.001Arsenic 0.003Copper 0.015Lead 0.025Silver 0.010Thallium 0.003Tin 0.010Zinc 0.0351.2 The test methods appear in the following order:SectionsAntimony by the Rhodamine B Spectrophotometric Method0.0002 % to 0.0010 %62-72Arsenic by the Molybdenu

4、m Blue Spectrophotometric Method0.001 % to 0.005 %40-50Copper by the Neocuproine Spectrophotometric Method 0.002 % to0.030 %10-19Copper, Lead, Silver, and Zinc by the Atomic Absorption Method0.004 % to 0.02 % Cu, 0.01 % to 0.05 % Pb, 0.004 % to 0.02 % Agand 0.01 % to 0.05 % Zn51-61Lead by the Dithiz

5、one Spectrophotometric Method 0.001 % to0.05 %20-29Thallium by the Rhodamine B Spectrophotometric Method0.0003 % to 0.005%30-39Tin by the 8-Quinolinol Spectrophotometric Method 0.0025 % to0.0150 %73-821.3 This standard does not purport to address all of thesafety concerns, if any, associated with it

6、s use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary information is given in Section 6, 25.8, 35.2, and 35.3.2. Referenced Documents2.1 ASTM S

7、tandards:2B440 Specification for CadmiumD1193 Specification for Reagent WaterE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated Materials

8、E55 Practice for Sampling Wrought Nonferrous Metals andAlloys for Determination of Chemical CompositionE60 Practice for Analysis of Metals, Ores, and RelatedMaterials by SpectrophotometryE88 Practice for Sampling Nonferrous Metals and Alloys inCast Form for Determination of Chemical CompositionE135

9、Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE173 Practice for Conducting Interlaboratory Studies ofMethods for Chemical Analysis of Metals3E1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method3. Terminology3.1

10、 For definitions of terms used in this test method, refer toTerminology E135.4. Significance and Use4.1 These test methods for the chemical analysis of cad-mium are primarily intended to test such material for compli-ance with compositional specifications in Specification B440.It is assumed that all

11、 who use these test methods will be trainedanalysts capable of performing common laboratory procedures1These test methods are under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and Related Materials and are the directresponsibility of Subcommittee E01.05 on Cu, Pb,

12、 Zn, Cd, Sn, Be, their Alloys, andRelated Metals.Current edition approved Jan. 27, 2012. Published February 2012. Originallyapproved in 1970. Last previous edition approved in 2011 as E396 05(2011). DOI:10.1520/E0396-12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact

13、ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor

14、 Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.skillfully and safely. It is expected that work will be performedin a properly equipped laboratory.5. Apparatus, Reagents, and Spectrophotometric Practice5.1 Apparatus and reagents required for each determinationare listed in separ

15、ate sections preceding the procedure. Theapparatus, standard solutions, and reagents shall conform to therequirements prescribed in Practices E50. Spectrophotometersshall conform to the requirements prescribed in Practice E60.5.2 Spectrophotometric practice prescribed in these meth-ods shall conform

16、 to Practice E60.6. Safety Hazards6.1 For precautions to be observed in the use of certainreagents in these test methods, refer to Practices E50.7. Sampling7.1 Wrought products shall be sampled in accordance withPractice E55. Cast products shall be sampled in accordancewith Practice E88. However, th

17、ese test methods do not super-sede any sampling requirements specified in a specific ASTMmaterial specification.8. Rounding Calculated Values8.1 Calculated values shall be rounded to the desired num-ber of places as directed in Practice E29.9. Interlaboratory Studies9.1 These test methods have been

18、evaluated in accordancewith Practices E173, unless otherwise noted in the precisionsection.COPPER BY THE NEOCUPROINESPECTROPHOTOMETRIC METHOD10. Scope10.1 This test method covers the determination of coppercontent from 0.002 % to 0.030 %.11. Summary of Test Method11.1 Copper is separated as cuprous

19、copper from othermetals by extraction of the copper-neocuproine complex withchloroform. Spectrophotometric measurement is made at ap-proximately 455 nm.12. Concentration Range12.1 The recommended concentration range is from 0.01mg to 0.15 mg of copper for each 25 mL of solution, using a1-cm cell.NOT

20、E 1This test method has been written for cells having a 1-cmlight path. Cells having other dimensions may be used, provided suitableadjustments can be made in the amounts of sample and reagents used.13. Stability of Color13.1 The color develops within 5 min and the extractedcomplex is stable. Howeve

21、r, because of the volatile nature ofthe solvent, it is advisable to take spectrophotometric readingspromptly.14. Interferences14.1 The elements ordinarily present do not interfere if theircontents are under the maximum limits shown in 1.1.15. Reagents15.1 Chloroform (CHCl3).15.2 Copper, Standard Sol

22、ution (1 mL = 0.01 mg Cu)Dissolve 0.1000 g of copper (purity: 99.9 % min) in 10 mL ofHNO3(1 + 1). Add 25 mL of water, heat to boiling, and boilgently for 2 min to eliminate oxides of nitrogen. Cool, transferto a 100-mL volumetric flask, dilute to volume, and mix.Transfer 5.00 mL to a 500-mL volumetr

23、ic flask. Add 1 mL ofHNO3(1 + 1), dilute to volume, and mix.15.3 Hydroxylamine Hydrochloride Solution (100 g/L)Dissolve 5.0 g of hydroxylamine hydrochloride(NH2OH HCl) in 50 mL of water. Prepare fresh as needed.15.4 Metacresol Purple Indicator Solution (1 g/L)Dissolve 0.100 g of metacresol purple to

24、gether with 1 pellet ofsodium hydroxide (NaOH) in about 10 mL of water bywarming. Dilute to 100 mL, and mix.15.5 Neocuproine Solution (1 g/L)Dissolve 0.10 g ofneocuproine (2,9-dimethyl-1,10-phenanthroline hemihydrate)in 100 mL of either methanol or 95 % ethanol.15.6 Sodium Citrate Solution (300 g/L)

25、Dissolve 300 g ofsodium citrate dihydrate in water, dilute to 1 L, and mix.15.7 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean reagent water as definedby Type II of Specification D1193. Other Types may be used ifthey effect no measurable change in the refere

26、nce solution orsample.16. Preparation of Calibration Curve16.1 Calibration Solution:16.1.1 Using pipets, transfer (2, 5, 10, 15, and 20) mL ofcopper solution (1 mL = 0.01 mg Cu) to five 150-mL beakers,and dilute to about 40 mL.16.1.2 Add 2 drops of metacresol purple indicator solution,and then add H

27、NO3(1 + 1) dropwise to the red color change ofthe indicator. Proceed as directed in 16.3.16.2 Reference SolutionAdd 40 mL of water to a 150- mLbeaker. Proceed as directed in 16.1.2.16.3 Color Development:16.3.1 Add 10 mL of NH2OH HCl solution, and stir. Add10 mL of sodium citrate solution, and stir.

28、 Add NH4OH to thepurple color of the indicator (pH about 8.5). Add 5.0 mL ofneocuproine solution, stir, and allow to stand for 5 min.NOTE 2The precipitate that may form upon addition of sodium citratesolution will redissolve when the pH is raised to 8.5 with NH4OH.16.3.2 Transfer to a 125-mL separat

29、ory funnel marked at 80mL, and dilute to the mark with water. Add 25.0 mL of CHCl3.Shake vigorously for 45 s, and allow the layers to separate.Draw off and discard about 1 mL of the CHCl3layer to rinsethe stem of the separatory funnel.16.4 Spectrophotometry:16.4.1 Multiple-Cell SpectrophotometerMeas

30、ure the cellcorrection using absorption cells with a 1-cm light path and aE396 1212light band centered at approximately 455 nm (Note 3). Usingthe test cell, take the spectrophotometric readings of thecalibration solutions.NOTE 3Avoid transfer of water to the absorption cell in the followingmanner. I

31、nsert a loose plug of sterilized absorbent cotton into the stem ofeach separatory funnel. Just prior to filling the absorption cell with thesolution in the separatory funnel, discard about 1 mL of the CHCl3layerthrough the cotton plug and immediately transfer a suitable portion of theCHCl3layer into

32、 the dry absorption cell.16.4.2 Single-Cell SpectrophotometerTransfer a suitableportion of the reference solution to an absorption cell with a1-cm light path and adjust the spectrophotometer to the initialsetting, using a light band centered at approximately 455 nm(Note 1). While maintaining this ad

33、justment, take the spectro-photometric readings of the calibration solutions.16.5 Calibration CurvePlot the net spectrophotometricreadings of the calibration solutions against milligrams ofcopper per 25 mL of solution.17. Procedure17.1 Test SolutionTransfer a 0.5-g sample, weighed to thenearest 1 mg

34、, to a 150-mL beaker. Add 5 mL of HNO3(1 + 1).When dissolution is complete, add 20 mL of water and boilgently to eliminate oxides of nitrogen. Cool, dilute to about 40mL, and add 2 drops of metacresol purple indicator solution.Proceed as directed in 17.3.17.2 Reference SolutionCarry a reagent blank

35、through theentire procedure using the same amount of all reagents with thesample omitted, for use as the reference solution.17.3 Color DevelopmentProceed as directed in 16.3.17.4 SpectrophotometryProceed as directed in 16.4.18. Calculation18.1 Convert the net spectrophotometric reading of the testso

36、lution to milligrams of copper by means of the calibrationcurve. Calculate the percentage of copper as follows:Copper, % 5 A/B 3 10! (1)where:A = copper found in the 25 mL of final test solution, mg,andB = sample represented in 25 mL of final test solution, g.19. Precision and Bias19.1 PrecisionEigh

37、t laboratories cooperated in testingthis test method and obtained the data summarized in Table 1.19.2 AccuracyNo certified reference materials suitablefor testing this test method were available when the interlabo-ratory testing program was conducted. The user of this testmethod is encouraged to emp

38、loy accepted reference materials,if available, to determine the accuracy of this test method asapplied in a specific laboratory.19.3 E173 has been replaced by Practice E1601. The repro-ducibility Index R2corresponds to the Reproducibility Index Rof Practice E1601. Likewise the Repeatability Index R1

39、corre-sponds to the Repeatability Index r of Practice E1601.LEAD BY THE DITHIZONESPECTROPHOTOMETRIC METHOD20. Scope20.1 This test method covers the determination of lead incontent from 0.001 % to 0.05 %.21. Summary of Test Method21.1 Lead dithizonate is extracted with chloroform from abuffered cyani

40、de solution at a pH of 8.5. The excess dithizonein the chloroform is then removed by extraction with anammoniacal sulfite solution. spectrophotometric measurementis made at approximately 515 nm.22. Concentration Range22.1 The recommended concentration range is from 0.005mg to 0.050 mg of lead for ea

41、ch 25 mL of solution, using a1-cm cell (Note 1).23. Stability of Color23.1 The color is stable for at least2hifprotected fromdirect sunlight; however, because of the volatile nature of thesolvent, it is advisable to take spectrophotometric readingspromptly.24. Interferences24.1 The elements ordinari

42、ly present in cadmium do notinterfere if their contents are under the maximum limits shownin 1.1.25. Reagents25.1 Ascorbic Acid.25.2 Bromine Water (Saturated).25.3 Chloroform (CHCl3).25.4 Dithizone Solution (0.01 g/L of CHCl3)Dissolve0.05 g of dithizone (diphenylthiocarbazone) in a freshlyopened 700

43、-g bottle of CHCl3. Mix several times over a periodof several hours. Store in a cool, dark place. Just before use,dilute 50 mL of this solution to 500 mL with CHCl3in a dryborosilicate bottle or flask, and mix.25.5 Lead, Standard Solution (1 mL = 0.005 mg Pb)Dissolve 0.1000 g of lead (purity: 99.9 %

44、 min) in 20 mL ofHNO3(1 + 1), and boil gently to eliminate oxides of nitrogen.Cool, transfer to a 200-mL volumetric flask, dilute to volume,and mix. Transfer 5.00 mL to a 500-mL volumetric flask, diluteto volume, and mix. Prepare the final solution fresh as needed.25.6 Metacresol Purple Indicator So

45、lution (1 g/L)Proceed as directed in 15.4.25.7 Potassium Cyanide Solution (200 g/L)Dissolve 200g of potassium cyanide (KCN) (low in lead and sulfide)(Warning See 25.8) in water, and dilute to 1 L. Bring to aboil and boil for 2 min. Cool, and store in a polyethylene bottle.TABLE 1 Statistical Informa

46、tionSpecimenCopper Found,%Repeatability(R1, E173)Reproducibility(R2, E173)1 0.0074 0.003 0.00132 0.0173 0.0018 0.0031E396 121325.8 Sodium Sulfite Wash SolutionDissolve1gofsodiumsulfite (Na2SO3) in about 300 mL of water in a 1-L volumetricflask. Add 20 mL of the KCN solution and 475 mL of NH4OH(1 + 1

47、) which has been prepared from a freshly opened bottle.Dilute to volume, and mix. Store in a polyethylene bottle.(WarningThe preparation, storage, and use of KCN solu-tions require care and attention. Avoid inhalation of fumes andexposure of the skin to the chemical and its solutions. Do notallow so

48、lutions containing cyanide to come in contact withstrongly acidic solutions. Work in a well-ventilated hood. Referto Section 8 of Practices E50.)25.9 Sodium Tartrate Solution (250 g/L)Dissolve 50 g ofsodium tartrate dihydrate in water, and dilute to 200 mL.25.10 Thioglycolic Acid Solution (1 + 99)Di

49、lute 1.0 mLof thioglycolic acid (mercaptoacetic acid) to 100 mL withwater. Refrigerate both the concentrated and diluted acidsolutions. Do not use concentrated acid that is more than 1 yearold, nor diluted acid that has stood for more than 1 week.25.11 Purity of WaterUnless otherwise indicated, refer-ence to water shall be understood to mean reagent water asdefined by Type II of Specification D1193. Other Types may beused if they effect no measurable change in the referencesolution or sample.26. Preparation of Calibration Curve2