1、Designation: E 1834 96 (Reapproved 2002)Standard Test Method forDetermination of Lead in Nickel Alloys by ElectrothermalAtomic Absorption Spectrometric Method1This standard is issued under the fixed designation E 1834; the number immediately following the designation indicates the year oforiginal ad
2、option or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of lead innickel and nickel
3、 alloys in the concentration range of0.00005 % to 0.001 % by electrothermal atomic absorptionspectrometry.NOTE 1If this test method is used to test materials having contentsless than 0.0001 % lead, users in different laboratories will experiencemore than the usual 5 % risk that their results will di
4、ffer by more than50 % relative error.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 appro-priate safety and health practices and determine the applica-bility of regulatory lim
5、itations prior to use. For specific hazardsassociated with the use of this practice see Practices E 50.2. Referenced Documents2.1 ASTM Standards:2E 50 Practices for Apparatus, Reagents, and Safety Precau-tions for Chemical Analysis of Metals, Ores, and RelatedMaterialsE 1184 Practice for Electrother
6、mal (Graphite Furnace)Atomic Absorption AnalysisE 1452 Practice for Preparation of Calibration Solutions forSpectrophotometric and Spectroscopic Atomic AnalysisE 1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical MethodE 1770 Practice for Optimization o
7、f Electrothermal AtomicAbsorption Spectrometric Equipment2.2 ISO Standards:ISO Standard 11437Nickel AlloysDetermination ofTrace-Element ContentElectrothermal Atomic Absorp-tion Spectrometric MethodPart 2: Determination of LeadContent3ISO Guide 5725Accuracy, Trueness, and Precision ofMeasurements, Me
8、thods and Results33. Summary of Test Method3.1 The sample is dissolved in a mixture of nitric acid,hydrofluoric acid, and water. The sample and a nickel-ammonium phosphate matrix modifier are injected into theelectrothermal atomizer of an atomic absorption spectrometer,which is provided with a backg
9、round corrector. Measurementof the absorbance is made at a wavelength of 283.3 nm. Thelead concentration is determined from a calibration curveestablished with nickel solutions containing a known amountof lead.4. Significance and Use4.1 This test method is intended to be used for the determi-nation
10、of trace levels of lead in nickel and nickel alloys. It isassumed that the procedure will be performed by trainedanalysts capable of performing common laboratory practicesskillfully and safely. It is expected that the work will beperformed in a properly equipped laboratory and proper wastedisposal p
11、rocedures will be followed.5. Apparatus5.1 Atomic Absorption Spectrometer, with electrothermalatomizer, equipped with an appropriate background corrector, asignal output device, such as a video display screen, a digitalcomputer, a printer or strip chart recorder, and an autosampler.5.2 Pyrolytically
12、 Coated Graphite Tubes, grooved, con-forming to the instrument manufacturers specifications.5.3 Pyrolytic Graphite Platforms, Lvov design, fitted to thetubes specified in 5.2.5.4 Radiation Source, lead hollow cathode lamp, or elec-trodeless discharge lamp with an appropriate power supply.1This test
13、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 and Co and High Temperature Alloys.Current edition approved Oct. 10, 1996. Published December 1996.2For referenced ASTM s
14、tandards, 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 onthe ASTM website.3Available from American National Standards Institute, 25 W. 43rd St., 4thFloor, Ne
15、w York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Instrument Parameters and Criteria6.1 The atomic absorption spectrometer and electrothermalatomizer are satisfactory if after adjustment of the instrumentsand optimi
16、zation of the furnace heating program as describedin Practice E 1770, they meet the criteria given in 6.4-6.7.6.2 Calibration solutions S0through S3prepared in accor-dance with 7.9 and summarized in Table 1 shall be used fortesting criteria.6.3 The parameters for the determination of lead and theest
17、ablishing of the instrument criteria are as follows:6.3.1 The injection volume is 20 L.6.3.2 The peak area absorbance integration measurementsshall be at a wavelength of 283.3 nm.6.4 Characteristic MassThe characteristic mass deter-mined in accordance with Practice E 1770 shall be within 20 %of that
18、 given in the manufacturers literature.6.5 PrecisionThe variability obtained from calibrationsolution S3shall not exceed 10 % of the mean absorbance ofthe same solution, and the variability of calibration solution S1shall not exceed 4 % of the mean absorbance of solution S3when determined in accorda
19、nce with Practice E 1770.6.6 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 in the test solution or 0.2 ppm in the originalsample).6.7 LinearityThe linearity of the calibration as deter-mined in Practice E 1770 shall n
20、ot be less than 0.7.7. Reagents7.1 Purity and Concentration of ReagentsThe purity andconcentration of common chemical reagents shall conform toPractices E 50. The reagents should be free of or containminimal amounts (0.01 g/g) of lead.7.2 Dissolution Acid MixtureTo 150 mL water carefullyadd 150 mL n
21、itric acid and 150 mL hydrofluoric acid. Mix andstore in plastic bottle.7.3 Pure Nickel Metal99.9 % minimum purity nickel, andshall contain less than 0.1 ppm lead.7.4 Nickel, Stock Solution (50 g/L)Dissolve 25 6 0.1gofthe pure nickel in 200 mL of nitric acid (1:1) in a 600 mLbeaker. Cool the solutio
22、n 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 nickelpowder, the solution must be filtered to remove undissolved carbon.7.5 Nickel, Solution (5.0
23、g/L)Transfer 10.0 mL of theNickel Stock Solution to a 100 mL volumetric flask. Dilute tothe mark with water and mix.7.6 Nickel Nitrate-Ammonium Phosphate Matrix ModifierSolutionDissolve 6.0 6 0.1 g high purity ammonium dihy-drogen phosphate (NH4H2PO4) in 50 mLwater. Transfer to 100mL volumetric flas
24、k and add 20 mL of nickel solution (7.5).Dilute with water and mix. This solution shall be freshlyprepared.7.7 Lead Reference Solution (100 mg/L)Dissolve 0.100 60.001 g of lead metal (99 % minimum purity) in 20 mL nitricacid (1:1) in a 250-mL beaker. Heat to assist dissolution. Cooland transfer to 1
25、-L volumetric flask, dilute to mark with waterand mix. Store in polypropylene or high density polyethylenebottle.7.8 Lead Standard Solution (1.0 mg/L)Pipette 10.0 mL ofthe lead reference solution (7.7) into a 1-L volumetric flask.Add 20 mL nitric acid and dilute to volume with water andmix. This sol
26、ution shall be freshly prepared.7.9 Calibration SolutionsTransfer 10.0 mL nickel solu-tion (50 g/L) to each of six 100 mL volumetric flasks. Addrespectively 0, 1.0, 2.0, 3.0, 4.0, and 6.0 mL of lead standardsolution (7.8). Dilute with water and mix. These calibrationsolutions contain 0, 10.0, 20.0,
27、30.0, 40.0 and 60.0 g Pb/L.These calibration solutions shall be identified as calibrationsolutions S0through S5, respectively (see Table 1).8. Sampling and Sample Preparation8.1 Sampling and sample preparation are to be performedby procedures agreed upon between buyer and seller.8.2 The sampling pro
28、cedure 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 melting, then milling a laboratory sample from the solid. Arc meltingof the sample or induction melting of the sample under vac
29、uum 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 performed only with at least a partial inertatmosphere.8.3 In most cases the laboratory sample is in the form ofhomogeneous
30、 turnings, millings or drillings and no furthermechanical preparation of the sample is necessary.8.4 The laboratory sample shall be cleaned by first washingin pure acetone and drying in air.8.5 If brazed alloy tools are used in the preparation of thesample, the sample shall be further cleaned by pic
31、kling indilute nitric acid for a few minutes. The sample shall then bewashed several times with water followed by several washeswith acetone and air dried.9. Procedure9.1 Preparation of Test SolutionTransfer 0.50 g sample,weighed to the nearest mg, to a 100 mL PTFE beaker. Add 20mL of the dissolutio
32、n acid mixture (7.2). Apply sufficient heatto initiate and maintain the reaction until dissolution is com-plete. Transfer solution to a 100 mL volumetric flask, cool, anddilute to volume with water.TABLE 1 Lead Concentration of Calibration SolutionsCalibrationSolutionConcentration of Pb in Calibrati
33、onSolutionPb Concentration inCalibration SolutionCorresponds toConcentration of Pb inSampleAg/L ng/mL ppm (g/metric ton)S000 0S110 10 2S220 20 4S330 30 6S440 40 8S560 60 12ABased 0.500 g sample/100 mL sample solution (9.1).E 1834 96 (2002)2NOTE 4It may be desirable to reduce the sample solution to w
34、et salts(approximately 5 mL). This will reduce the presence of excess fluorideions (a known interference for a number of elements determined byelectrothermal atomic absorption spectrometry).NOTE 5Certain nickel alloys may be difficult to dissolve in the nitricacid-hydrofluoric acid mixture. In such
35、cases, the proportions of thedissolution acid mixture may be adjusted, but a corresponding blank testis necessary.9.2 A reagent blank shall be carried along during the entireprocedure.9.3 Dilution for samples containing up to 5 ppm lead:9.3.1 Transfer 1.0 mL of each test solution containing up to25
36、g/L lead, the reagent blank, and each of the calibrationsolutions from S0through S3intoa5mLplastic vial using amicropipette. Add 100 L of the matrix modifier (7.6) using amicropipette and mix.9.4 Dilution for samples containing from 5 to 10 ppm lead:9.4.1 Transfer 0.50 mL of each test solution conta
37、iningbetween 25 g/L and 50 /L of lead, the reagent blank, and ofthe calibration solutions from S0through S5into 5 mL plasticvials using a micropipet.Add 0.50 mL nickel solution (7.5) and100 L of the matrix modifier solution (7.6) to each using amicropipet and mix.NOTE 6If the electrothermal atomizer
38、 is fitted with an autosampler,the modifier addition, dilution, and mixing can be done in the autosamplercups.NOTE 7The mixing can be done by repeatedly charging and discharg-ing the contents of the plastic vial using a larger micropipette.9.5 Analyze several replicates of the S0solution to establis
39、ha stable instrument response. Set the last replicate to zero.9.6 Starting with the appropriately diluted calibration solu-tions (9.3 or 9.4), inject 20 L into the electrothermal atomizerand atomize the sample. Record the absorbance. Run eachcalibration solution in triplicate.9.7 Inject 20 L of the
40、appropriately diluted reagent blank(9.3 or 9.4) into the electrothermal atomizer and atomize thesample. Record the absorbance. Run at least in duplicate.9.8 Check calibration slope by injecting and atomizing 20L of S0and the highest calibration solution used. Run intriplicate and record absorbance v
41、alues.9.9 Inject 20 L of the test solution and atomize. Recordabsorbance values. Run each sample at least in duplicate.9.9.1 Repeat step 9.9 with the next test solution.9.10 Repeat steps 9.8, 9.9, and 9.9.1 until all the testsolutions are measured.9.11 Calculate the means of the absorbance measureme
42、ntsobtained in steps 9.6-9.10.10. Calibration Graphs and Calculation10.1 Most electrothermal atomizers controlled 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 gr
43、aph and per-form the calculation in accordance with 10.2-10.9.10.2 Subtract the mean absorbance value obtained for the S0calibration solution, the reagent blank, from the mean absor-bance values obtained for each of the remaining calibrationsolutions.10.3 Construct a graph relating the mean absorban
44、ce valuesobtained for the calibration solutions (10.2) to their leadcontent in g/L.10.4 Using the mean absorbance obtained for the reagentblank solution (9.7) determine the lead concentration of thereagent blank solution from the calibration curve (10.3).10.5 If the calibration check measurement obt
45、ained in 9.8shows that the calibration curve has drifted slightly, adjust thecalibration curve accordingly.10.6 Using the mean adjusted absorbance values obtained in9.9 determine the lead content of the two test solutions.10.7 Repeat instructions given in 10.5 and 10.6 until thelead content of the r
46、emaining test solutions are obtained.10.8 Subtract the lead content of the reagent blank solution(10.4) from the lead content of the test solutions found in 10.6and 10.7.10.9 Calculate the lead content of the test sample, in ppm(g/metric ton), using the formula:Pb in ppm 5 c/10 m for dilutions made
47、in accordance with 9.3 !(1)Pb in ppm 5 c/20 m for dilutions made in accordance with 9.4!where:c = the lead concentration, in g/L in the test solution, ascalculated in 10.8.m = the mass, in g, of the test portion (9.1).TABLE 2 Nominal Composition of Test Samples, %Sample Pb Co Cr Mo Ta Ti Al Hf W V N
48、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 Nic
49、kelAlloysTestMaterialAverage PbFound, ppmRepeatability(sr, ISO 5725)AReproducibility(SR, ISO 5725)BRrel %6 0.04 0.27 0.26 6503 0.14 0.33 0.42 3001 1.6 0.26 0.45 284 4.0 0.59 0.86 212 9.6 1.31 2.13 225 10.7 1.42 2.06 19AEquivalent to 2.8 3 SMwhere SMis minimum standard deviation (see PracticeE 1601).BEquivalent to R, reproducibility index (see Practice E 1601).E 1834 96 (2002)311. Test Reports11.1 Report the following information:11.1.1 The reference to this test method;11.1.2 The results of the analysis;11.1.3 The number of independent r
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