1、Designation: E 1852 96 (Reapproved 2001)Standard Test Method forDetermination of Low Levels of Antimony in Carbon andLow-Alloy Steel by Electrothermal Atomic AbsorptionSpectrometry1This standard is issued under the fixed designation E 1852; the number immediately following the designation indicates
2、the year oforiginal adoption 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 an
3、timonyin carbon and low-alloy steel in the 0.0005 through 0.010 %range.1.2 If this test method is used to test materials havingcontents less than 0.001 % antimony, users of different labo-ratories will experience more than the usual 5 % risk that theirresults will differ by more than 50 % relative e
4、rror.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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referen
5、ced Documents2.1 ASTM Standards:2E50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated MaterialsE 1184 Practice for Electrothermal (Graphite Furnace)Atomic Absorption AnalysisE 1452 Practice for Preparation of Calibration Solutions forSpe
6、ctrophotometric and for Spectroscopic Atomic Analy-sesE 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:ISO 5725 Precision of Test Meth
7、odsDetermination ofRepeatability and Reproducibility for a Standard TestMethod by Inter-Laboratory Tests3ISO 10698 SteelDetermination of Antimony ContentElectrothermal Atomic Absorption SpectrometricMethod33. Summary of Test Method3.1 The sample is dissolved in hydrochloric and nitric acidsand dilut
8、ed to volume. An appropriate aliquot is injected intothe electrothermal atomizer of an atomic absorption spectrom-eter, which is equipped with a background correction. Thesample is dried, pyrolized, and atomized. The absorbance ofthe radiation from the external light source is measured andcompared t
9、o the absorbance of samples to which knownamounts of the sought element were added.NOTE 1In general, the deuterium correction system should be able tocorrect for the broad-band background absorbance up to 0.5 to 0.6absorbance units. Zeeman systems should compensate for backgroundlevels as high as 1.
10、0 to 1.5 absorbance units.4. Significance and Use4.1 This test method is to be used for the determination oftrace levels of antimony in carbon and low-alloy steel. It isassumed that the procedure will be performed by trainedanalysts capable of performing common laboratory practicesskillfully and saf
11、ely. It is expected that the work will beperformed in a properly equipped laboratory and proper wastedisposal procedures will be followed.5. Apparatus5.1 Atomic Absorption Spectrometer with ElectrothermalAtomizer, equipped with background corrector and appropriatesignal output device, such as video
12、display screen, digitalcomputer, printer or strip chart recorder, and autosampler. It is1This test method is under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and Related Materials and is the directresponsibility of Subcommittee E01.01 on Iron, Steel, and Ferroall
13、oys.Current edition approved Dec. 10, 1996. Published February 1997.2For 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 onthe ASTM w
14、ebsite.3Available from American National Standards Institute, 11 West 42nd Street,13th Floor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.recommended that the instrument meet the following perfor-mance requirem
15、ents after adjusting the instrument and opti-mizing the furnace heating program as described in PracticeE 1770.5.1.1 The characteristic mass determined in accordancewith Practice E 1770 for antimony shall be less than 25 pg orwithin the manufacturers tolerance.5.1.2 The minimum precision of the most
16、 concentratedblank addition solution shall not exceed 10 % of the meanabsorbance of the same solution. The minimum precision ofthe least concentrated blank addition solution (excluding So-lution B0) shall not exceed 4 % of the mean absorbance of themost concentrated blank addition solution when dete
17、rmined inaccordance with Practice E 1770.5.1.3 The limit of detection of antimony as described inPractice E 1770 shall be less than 20 pg.5.1.4 Unless the instrument is provided with automaticcurve correction circuitry, the graph linearity shall not be lessthan 0.95 when determined in accordance wit
18、h PracticeE 1770.5.2 Graphite Tubes, with pyrolytic coating and grooves forgraphite platform, suitable for use with the electrothermalatomizer used.5.3 Graphite Platform, pyrolytic graphite, Lvov design, tofit graphite tubes specified in 5.2.5.4 LabwareTo prevent contamination of the sample(s),all b
19、eakers, lids, volumetric flasks, and funnels must be cleanedwith hot HNO3(1 + 1) before use.6. Reagents6.1 Purity and Concentration of ReagentsThe purity andconcentration of common chemical reagents shall conform toPractices E50. It is important that antimony shall not exceed0.01 g/mL in each of the
20、 reagents and 0.001 g/mL in thewater.6.2 Antimony Stock Solution (1 mL = 1 mg Sb)Dissolve0.100 6 0.0001 g high-purity antimony (minimum 99.9 % Sb)in 30 mL HCl + 5 mL HNO3in a 100-mL beaker. Boil gentlyto expel oxides of nitrogen. Cool and transfer the solution intoa 100-mL volumetric flask. Dilute t
21、o mark with HNO3(1+1)and mix. Store in polypropylene or high density polyethylenebottle.6.3 Antimony Standard Solution (1 mL = 10 g Sb)Transfer 1.0 mL of the antimony stock solution to a 100-mLvolumetric flask, dilute to the mark with HNO3(1 + 1), andmix. Prepare this solution immediately before use
22、.7. Sampling and Sample Preparation7.1 Sampling and sample preparation is to be performed byprocedures agreed on between buyer and seller.7.2 The sampling procedures shall not involve any steps oroperations that can result in the loss of antimony in the sample.NOTE 2Arc melting of the sample or indu
23、ction melting of the sampleunder vacuum may result in significant loss of several elements that havea low vapor pressure. Arc melting of the sample should be avoided andinduction melting should be performed only in an at least partial inertatmosphere.7.3 The laboratory sample is normally in the form
24、 ofturnings, millings, or drillings. No further mechanical prepa-ration of the sample is necessary.7.4 The laboratory sample shall be cleaned by first washingin acetone and air drying.7.5 If brazed alloy tools are used in the preparation of thesample, the sample shall be further cleaned by pickling
25、indiluted nitric acid for a few minutes. The sample shall then bewashed several times with water, then several times withacetone and air dried.8. Procedure8.1 Sample SizeFor samples containing between 0.0005and 0.0050 % antimony, the sample size shall be 1.00 g,weighed to the nearest 0.1 mg. For sam
26、ples containing between0.0050 and 0.010 % antimony, the sample shall be 0.25 gweighed to the nearest 0.1 mg.8.2 BlankSimultaneously with the sample, a blank testusing the same quantities of all reagents shall be carried along.The antimony contents of the blank should be no greater than10 ppb.8.3 Tes
27、t SolutionTransfer the test portion in accordancewith 8.1 into a 250-mL beaker. Add 5 mL HCl and 50 mLHNO3. Cover the beaker with a watch glass, heat gently untilthe reaction ceases, and boil for 1 min to remove the oxides ofnitrogen.8.3.1 If sample contains tungsten or niobium, or both,transfer tes
28、t portion (see 9.1) to a 100-mLbeaker and add 1 mLorthophosphoric acid, 15 mL hydrochloric acid, and 5 mLnitric acid. Cover beaker with watch glass, and heat gently untilreaction ceases. Evaporate the solution to 2 to 3 mL; then add25 mL nitric acid. Boil for 1 min to remove nitrous oxides.Carry alo
29、ng a separate blank test corresponding to this proce-dure.8.3.2 Allow the solution, which may contain carbides, tocool. Add about 15 mL water, filter through medium texturefilter paper, and collect the filtrate in a 200-mL volumetricflask. Wash the filter paper several times with warm water andcolle
30、ct the washings in the flask. Dilute to the mark with waterand mix.8.4 Test Addition SolutionsTransfer separate 20.0-mL ali-quot of the test solution into a series of five 100-mLvolumetricflasks. Using a micropipette, inject the respective volumes ofantimony standard solution indicated in Table 1. D
31、ilute to themark with water and mix. These solutions are referred to as S0,S1,S2,S3, and S4, respectively.TABLE 1 Test Addition SolutionsName ofSolutionVolume ofAntimonyStandardSolutionAdded, LConcentrationof AntimonyAdded in TestAdditionSolutions,ng/mLCorresponding Mass ofAntimony Added, ngVolumeIn
32、jected,10 LVolumeInjected,50 LS0000.0.S1100 10 0.1 0.5S2200 20 0.2 1.0S3400 40 0.4 2.0S4500 50 0.5 2.5E 1852 96 (2001)28.5 Blank Addition SolutionsTransfer separate 20.0-mLaliquot of the blank solution into a series of five 100-mLvolumetric flasks. Using a micropipette, add the respectivevolumes of
33、antimony standard solution indicated in Table 2.Dilute to the mark with water and mix. These solutions arereferred to as B0,B1,B2,B3, and B4, respectively.8.6 Optical parameters used for the determination of anti-mony are given in Table 3.8.7 The atomic absorption spectrometer and the electrother-ma
34、l atomizer should be adjusted and optimized as described inPractices E 1184, and E 1770.NOTE 3The volume injected into the atomizer should be between 10and 50 L, depending on sensitivity, matrix interference, backgroundcorrection, and range of linearity. The volume 20 L is usually correct.8.8 Using
35、the autosampler, inject the predetermined volumeof the test solution and blank addition solutions in increasingorder into the atomizer. Atomize each solution three times.Record the three peak height readings.NOTE 4In most instances, the use of peak area integration is prefer-able.8.9 Check the instr
36、uments for memory effects, especially athigh analyte levels, by running the blank firing program. Resetthe baseline to zero if necessary. Record the peak heightreading for each determination (see Note 3).9. Plotting of Additions Graphs9.1 Calculate the average instrument readings for each ofthe blan
37、k addition solutions of 8.5 “B” against the mass ofantimony added, expressed in nanograms, in the blank additionsolutions.9.2 Calculate the average instrument readings for each ofthe test addition solutions of 8.5 “S” against the mass ofantimony added, expressed in nanograms, in the test additionsol
38、utions.NOTE 5In this test method, any nonspecific absorption effect iseliminated by the background correction of the instrument.Antimony maybe present in the reagents. If antimony is present in the reagents, this plotmay not pass through the origin.9.3 The standard additions graphs for the blank and
39、 thesample should be parallel.10. Calculation10.1 Most electrothermal atomizers controlled by comput-ers will calculate the means, establish their own calibrationcurves, and calculate and display the results. If using instru-ments not having this capability, prepare the calibrationsgraphs and perfor
40、m the calibrations in accordance with 10.2and 10.3.10.2 Determine the masses of antimony in the test and blankaddition solutions, mSb.1and mSb.0, respectively, expressed innanograms, as the two intercepts on the mass axis by extrapo-lating the resulting straight lines in the two additions graphs(see
41、 9.1 and 9.2). The difference (mSb.1 mSb.0) gives the netmass of antimony, mSb, in the test solution (Solution S1).10.2.1 The net mass of antimony, mSb, may also be calcu-lated using the least-square-fit method applied to the twostraight lines, the blank addition solutions (solutions“ B”), andthe te
42、st addition solutions (solutions “S”). The equation of thestraight line relating absorbance to mass is as follows:y 5 a 1 bm (1)where:a and b = constants that correspond respectively to theintercept on the y-axis and the slope of thestraight line. Calculate b and a using the least-square-fit method
43、as follows:b 5 n(miyi2 (mi(yi#/n(mi2(mi!2# (2)a 5 1/n! (yi2 b(mi!The intercept on the x-axis with the straight line of the slopeb is (a/b):mSb.15 1/nb1! (yi2 b1(mi! (3)mSb.05 1/nb0! (yi2 b0(mi!mSb5 mSb.12 mSb.0where:b = coefficient of regression,n = number of solutions analyzed,a = intercept on the
44、y axis;mi= mass of antimony added in the test or blankaddition solutions, ng,yi= absorbance corresponding to the test or blankaddition solutions,mSb.1= mass of the antimony obtained from the testaddition solutions, ng,mSb.0= mass of the antimony obtained from the blankaddition solutions, ng, andmSb=
45、 mass of antimony in the test addition solution (S0),ng.10.3 The antimony content, wSb, as a percentage by mass isobtained from the equation as follows:wSb5 100 mSb105V2/V1! V4/V3!#/109m (4)5 100 mSb105/V1! 200/20!#/109m 5 0.1 mSb/mV1(4)TABLE 2 Blank Addition SolutionsName ofSolutionVolume ofAntimon
46、yStandardSolutionAdded, LConcentrationof AntimonyAdded in BlankAdditionSolutions,ng/mLCorresponding Mass ofAntimony Added, ngVolumeInjected,10 LVolumeInjected,50 LB0000.0.B1100 10 0.1 0.5B2200 20 0.2 1.0B3400 40 0.4 2.0B4500 50 0.5 2.5TABLE 3 Optical Parameters for Antimony DeterminationItem Paramet
47、erRadiation Source electrodeless discharge lamp (EDL) or hollow cathodelampLamp Current As recommended by lamp manufacturerSlit As recommended by instrument manufacturerWavelength 217.6 nmBackground Corrector yesE 1852 96 (2001)3where:V1= volume injected of a series of test addition solutionsand of
48、the blank addition solution (see Table 1 andTable 2), L,V2= volume of a series of test addition solutions and blankaddition solutions (see 7.4 and 7.5), mL,V3= volume of the aliquot of the test and blank solution(see 7.4 and 7.5), mL,V4= volume of the test and blank solutions (see section7.3.2), mL
49、andm = mass of the test portion in 7.1, g.11. Report11.1 Report the following information:11.1.1 All information necessary for the identification of thesample, the laboratory, and the date of analysis,11.1.2 The method used by reference to this test method,11.1.3 The results and the units in which they are expressed,11.1.4 Any unusual features noted during the determination,and11.1.5 Any operation not specified in this test method, orany optional operations which may have influenced the result.12. Precision and Bias12.1 PrecisionSixt
