1、Designation: E 1834 09Standard Test Method forDetermination of Lead in Nickel Alloys by Graphite FurnaceAtomic Absorption Spectrometry1This standard is issued under the fixed designation E 1834; 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 test method covers the determination of lead innickel alloys in the concentration range 0
3、.00005 % to 0.001 %by graphite furnace atomic absorption spectrometry (GF-AAS).NOTE 1If this test method is used to test materials having contentsless than 0.0001 % lead, users in different laboratories may experiencemore than the usual 5 % risk that their results will differ by more than50 % relati
4、ve error.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 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 estab
5、lish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specific hazardsassociated with the use of this test method, see Practices E50.2. Referenced Documents2.1 ASTM Standards:2E50 Practices for Apparatus, Reagents, and Safety Consi
6、d-erations for Chemical Analysis of Metals, Ores, andRelated MaterialsE 135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE 882 Guide for Accountability and Quality Control in theChemical Analysis LaboratoryE 1184 Practice for Electrothermal (Graphite Furnace)Ato
7、mic Absorption AnalysisE 1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical MethodE 1770 Practice for Optimization of Electrothermal AtomicAbsorption Spectrometric Equipment2.2 ISO Standards:3ISO 5725:1986 Precision of Test Methods Determinationof Repea
8、tability and Reproducibility for a Standard TestMethod by Inter-Laboratory TestsISO 11437:1994 Nickel Alloys Determination of Trace-Element Content Electrothermal Atomic AbsorptionSpectrometric MethodPart 2: Determination of LeadContent3. Terminology3.1 DefinitionsFor definitions of terms used in th
9、is testmethod, refer to Terminology E 135.4. Summary of Test Method4.1 The sample is dissolved in a mixture of HNO3, HF, andwater and diluted to a known volume. A nickel-ammoniumphosphate matrix modifier is added to an appropriate aliquotand a portion is injected into the graphite furnace atomizer o
10、fan atomic absorption spectrometer, which is provided with abackground corrector. The sample is dried, pyrolized, andatomized. The absorbance of the resonance spectral line of leadis measured at 283.3 nm and compared with that frommatrix-matched calibration solutions.5. Significance and Use5.1 This
11、test method is used for the determination of tracelevels of lead in nickel alloys by GF-AAS to check compliancewith compositional specifications. It is assumed that theprocedure will be performed by trained analysts capable ofperforming common laboratory practices skillfully and safely.It is expecte
12、d that the work will be performed in a properlyequipped laboratory and proper waste disposal procedures will1This test method is under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and Related Materials and is the directresponsibility of Subcommittee E01.08 on Ni an
13、d Co and High Temperature Alloys.Current edition approved July 15, 2009. Published August 2009. Originallyapproved in 1996. Last previous edition approved in 2002 as E 1834 96 (2002).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.
14、org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Driv
15、e, PO Box C700, West Conshohocken, PA 19428-2959, United States.be followed. Appropriate quality control practices must befollowed such as those described in Guide E 882.6. Apparatus6.1 Atomic Absorption Spectrometer, with graphite furnaceatomizer, and equipped with an appropriate background cor-rec
16、tor, a signal output device, such as a video display screen, adigital computer, a printer or strip chart recorder, and anautosampler.6.2 Pyrolytically Coated Graphite Tubes, grooved, con-forming to the instrument manufacturers specifications.6.3 Pyrolytic Graphite Platforms, Lvov design, fitted to t
17、hetubes specified in 6.2.6.4 Radiation Source, lead hollow cathode lamp, or elec-trodeless discharge lamp with an appropriate power supply.7. Instrument Parameters and Criteria7.1 The atomic absorption spectrometer and graphite fur-nace atomizer are satisfactory if, after adjustment of theinstrument
18、 and optimization of the furnace heating program asdescribed in Practice E 1770, they meet the criteria given in7.4-7.7. For general discussion of the theory and instrumentalrequirements of GF-AAS, see Practice E 1184.7.2 Calibration solutions S0through S5prepared in accor-dance with 8.9 and summari
19、zed in Table 1 shall be used fortesting criteria.7.3 The parameters for the determination of lead and theestablishing of the instrument criteria are as follows:7.3.1 The injection volume is 20 L.7.3.2 The peak area absorbance integration measurementsshall be at a wavelength of 283.3 nm.7.4 Character
20、istic MassThe characteristic mass deter-mined in accordance with Practice E 1770 shall be within 20 %of that given in the manufacturers literature.7.5 PrecisionThe variability obtained from calibrationsolution S3shall not exceed 10 % of the mean absorbance ofthe same solution, and the variability of
21、 calibration solution S1shall not exceed 4 % of the mean absorbance of solution S3when determined in accordance with Practice E 1770.7.6 Limit of DetectionThe limit of detection of lead asdescribed in Practice E 1770 shall be less than 20 pg (equiva-lent to 1.0 g/L lead in the test solution or 0.2 g
22、/g in theoriginal sample).7.7 LinearityThe linearity of the calibration as deter-mined in Practice E 1770 shall be not less than 0.7.8. Reagents8.1 Purity and Concentration of ReagentsThe purity andconcentration of common chemical reagents and water shallconform to Practices E50. The reagents should
23、 be free of, orcontain minimal amounts ( 0.01 g/g) of, lead.8.2 Dissolution Acid MixtureTo 150 mL water carefullyadd 150 mL HNO3and 150 mL HF. Mix and store in plasticbottle.8.3 Pure Nickel Metal99.9 % minimum purity nickel, andshall contain less than 0.1 g/g lead.8.4 Nickel, Stock Solution (50 g/L)
24、Dissolve 25 g 6 0.1 gof the pure nickel in 200 mL of HNO3(1 + 1) in a 600-mLbeaker. Cool the solution and transfer to a 500-mL volumetricflask. Dilute to the mark and mix.NOTE 2If large nickel turnings or chunks are used, gentle heating maybe required to complete the dissolution. When using carbonyl
25、 nickelpowder, the solution must be filtered to remove undissolved carbon.8.5 Nickel, Solution (5.0 g/L)Transfer 10.0 mL of theNickel Stock Solution to a 100-mL volumetric flask. Dilute tothe mark and mix.8.6 Nickel Nitrate-Ammonium Phosphate Matrix ModifierSolutionDissolve 6.0 g 6 0.1 g high purity
26、 ammoniumdihydrogen phosphate (NH4H2PO4) in 50 mL water. Transferto 100 mL volumetric flask and add 20 mL of nickel solution(8.5). Dilute and mix. This solution shall be freshly prepared.8.7 Lead Reference Solution (100 mg/L)Dissolve 0.100 g6 0.001 g of lead metal (99 % minimum purity) in 20 mLHNO3(
27、1 + 1) in a 250-mL beaker. Heat to assist dissolution.Cool and transfer to 1-L volumetric flask, dilute to mark, andmix. Store in polypropylene or high density polyethylenebottle.8.8 Lead Standard Solution (1.0 mg/L)Pipette 10.0 mL ofthe lead reference solution (8.7) into a 1-L volumetric flask.Add
28、20 mL HNO3, dilute to volume, and mix. This solutionshall be freshly prepared.8.9 Calibration SolutionsTransfer 10.0 mL of the nickelsolution (50 g/L) to each of six 100-mL volumetric flasks. Add(0, 1.0, 2.0, 3.0, 4.0, and 6.0) mL of lead standard solution,dilute, and mix. These calibration solution
29、s contain (0, 10.0,20.0, 30.0, 40.0, and 60.0) g/L lead. These calibrationsolutions shall be identified as calibration solutions S0throughS5, respectively (see Table 1).9. Sampling and Sample Preparation9.1 Sampling and sample preparation are to be performedby normal procedures agreed upon between t
30、he parties, or inthe event of a dispute, in accordance with the relevant standard,if one is available.9.2 The sampling procedure shall not involve any steps orprocedures that can result in the loss or pick up of lead in thesample.NOTE 3Sometimes a heterogeneous scrap composite is homogenizedby melti
31、ng, then milling a laboratory sample from the solid. Arc meltingof the sample or induction melting of the sample under vacuum can resultin significant loss of several elements, including lead, that have a lowvapor pressure. Arc melting of the sample should be avoided andinduction melting should be p
32、erformed only in a partially inert atmo-sphere.TABLE 1 Lead Concentration of Calibration SolutionsCalibrationSolutionConcentration of Pb in CalibrationSolutionPb Concentration inCalibration SolutionCorresponds toConcentration of Pb inSampleAg/L ng/mL g/gS000 0S110 10 2S220 20 4S330 30 6S440 40 8S560
33、 60 12ABased 0.500 g sample/100 mL sample solution (10.1).E18340929.3 Generally the laboratory sample is in the form ofhomogeneous turnings, millings, or drillings and no furthermechanical preparation of the sample is necessary.9.4 If it is suspected that the laboratory sample is contami-nated with
34、oil or grease, it shall be cleaned by washing withhigh purity acetone or other appropriate solvent and drying inair.9.5 If brazed alloy tools are used in the preparation of thesample, the sample shall be further cleaned by pickling indilute HNO3for a few minutes. The sample shall then bewashed sever
35、al times with water followed by several washeswith acetone or other appropriate solvent and air dried.10. Procedure10.1 Preparation of Test SolutionTransfer 0.50 g sample,weighed to the nearest mg, to a 100-mL PTFE beaker. Add 20mL of the dissolution acid mixture (8.2). Apply sufficient heatto initi
36、ate and maintain the reaction until dissolution is com-plete. Transfer solution to a 100-mL plastic volumetric flask,cool, and dilute to volume.NOTE 4It may be desirable to reduce the sample solution to wet salts(approximately 5 mL) which will reduce the presence of excess fluorideions (a known inte
37、rference for a number of elements determined byGF-AAS).NOTE 5Certain nickel alloys may be difficult to dissolve in theHNO3-HF mixture. In such cases, the proportions of the dissolution acidmixture may be adjusted, but a corresponding blank test is necessary.10.2 A reagent blank shall be carried alon
38、g during the entireprocedure.10.3 Dilution for samples containing up to 5 g/g lead:10.3.1 Transfer 1.0 mLof each test solution containing up to25 g/L lead, the reagent blank, and each of the calibrationsolutions from S0through S3into 5-mL plastic vials using amicropipette. Add 100 L of the matrix mo
39、difier (8.6) using amicropipette and mix.10.4 Dilution for samples containing from 5 to 10 g/g lead:10.4.1 Transfer 0.50 mL of each test solution containingbetween 25 g/L and 50 /L of lead, the reagent blank, andeach of the calibration solutions from S0through S5into 5-mLplastic vials using a microp
40、ipet. Add 0.50 mL nickel solution(8.5) and 100 L of the matrix modifier solution (8.6) to eachusing a micropipet and mix.NOTE 6If the graphite furnace atomizer is fitted with an autosampler,the matrix modifier addition, dilution, and mixing can be done in theautosampler cups.NOTE 7The mixing can be
41、done by repeatedly charging and discharg-ing the contents of the plastic vial using a larger micropipette.10.5 Analyze several replicates of the S0solution to estab-lish a stable instrument response. Set the last replicate to zero.10.6 Starting with the appropriately diluted calibration so-lutions (
42、10.3 or 10.4), inject 20 L into the graphite furnaceatomizer and atomize the sample. Record the absorbance. Runeach calibration solution in triplicate.10.7 Inject 20 L of the appropriately diluted reagent blank(10.3 or 10.4) into the graphite furnace atomizer and atomizethe sample. Record the absorb
43、ance. Run at least in duplicate.10.8 Check calibration slope by injecting and atomizing 20L of S0and the highest calibration solution used. Run intriplicate and record absorbance values.10.9 Inject 20 L of the test solution and atomize. Recordabsorbance values. Run each sample at least in duplicate.
44、10.9.1 Repeat step 10.9 with the next test solution.10.10 Repeat steps 10.8, 10.9, and 10.9.1 until all the testsolutions are measured.10.11 Calculate the means of the absorbance measurementsobtained in steps 10.6-10.10.11. Calibration Graphs and Calculation11.1 Most graphite furnace atomizers contr
45、olled by a com-puter will calculate the means, establish the calibration curvesand calculate and display the results. If using instruments nothaving this capability, prepare the calibration graph and per-form the calculation in accordance with 11.2-11.9.11.2 Subtract the mean absorbance value obtain
46、ed for the S0calibration solution from the mean absorbance values obtainedfor each of the remaining calibration solutions.11.3 Construct a graph relating the mean absorbance valuesobtained for the calibration solutions (11.2) to their leadcontent in g/L.11.4 Using the mean absorbance obtained for th
47、e reagentblank solution (10.7) determine the lead concentration of thereagent blank solution from the calibration curve (11.3).11.5 If the calibration check measurement obtained in 10.8shows that the calibration curve has drifted slightly, adjust thecalibration curve accordingly.11.6 Using the mean
48、adjusted absorbance values obtained in10.9 determine the lead content of the dupllicate test solutions.11.7 Repeat instructions given in 11.5 and 11.6 until the leadcontent of the remaining test solutions are obtained.TABLE 2 Nominal Composition of Test Samples, %Sample Pb Co Cr Mo Ta Ti Al Hf W V N
49、i1 0.0001 15 15 5 . 2.5 2.5 . . . Balance2 0.001 15 15 5 . 2.5 2.5 . . . Balance3 0.0001 10 8 . 2.5 1.5 5 1.5 10 . Balance4 0.0004 10 8 . 2.5 1.5 5 1.5 10 . Balance5 0.001 10 8 . 2.5 1.5 5 1.5 10 . Balance6 0.00005 14 10 3 . 4.5 6 . . 1 BalanceTABLE 3 Results of the Statistical Analysis, Lead in NickelAlloysTestMaterialAverage PbFound, g/gRepeatabilityIndex(Practice E 1601)ReproducibilityIndex(Practice E 1601)6 0.04 0.27 0.263 0.14 0.33 0.421 1.6 0.26 0.454 4.0 0.59 0.862 9.6 1.31 2.135 10.7 1.42 2.06E183409311.8 Subtract the lea
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