1、Designation: E 1446 05Standard Test Method forChemical Analysis of Refined Gold by Direct CurrentPlasma Emission Spectrometry1This standard is issued under the fixed designation E 1446; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, 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 analysis of refined gold forthe following elements having the following ch
3、emical compo-sition limits:Element Concentration Range, ppmCopper 17 to 300Iron 6 to 150Lead 17 to 100Palladium 7 to 350Silver 17 to 5001.2 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 ad
4、dress 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. Referenced Documents2.1 ASTM Standards:2B 562 Specif
5、ication for Refined GoldE29 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 Material3E 135 Terminology Relating to Analytical Chemistry fo
6、rMetals, Ores, and Related MaterialsE 173 Practice for Conducting Interlaboratory Studies ofMethods for Chemical Analysis of Metals3E 882 Guide for Accountability and Quality Control in theChemical Analysis LaboratoryE 1097 Guide for Direct Current Plasma Emission Spec-trometry AnalysisE 1601 Practi
7、ce for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology E 135.4. Summary of Test Method4.1 The sample is dissolved with acids. Calibration solu-tions are prepared
8、from pure reagents to match the samplematrix. Analysis is performed with the d-c argon plasmaoptical emission spectrometer. Element concentrations aremeasured by comparing emission intensities from the samplewith those of the calibration solutions. Copper is measured at327.3 nm or 324.7 nm; iron at
9、259.9 nm; lead at 405.7 nm;palladium at 340.4 nm; and silver at 328.0 nm or 338.3 nm.5. Significance and Use5.1 This test method for the analysis of fine gold is primarilyintended to test such material for compliance with composi-tional specifications. It is assumed that all who use this testmethod
10、will be trained analysts capable of performing commonlaboratory procedures skillfully and safely. It is expected thatwork will be performed in a properly equipped laboratory andoperated in accordance with Guide E 882.6. Interferences6.1 Spectral line interferences and spectrochemical back-ground eff
11、ects are overcome by preparing a matrix-matchedcalibration standard series to approximate the prepared sample.6.2 The analyte wavelengths mentioned herein have beenpreviously evaluated for spectral line interferences and foundto be the optimum emission wavelengths for refined gold1This test method i
12、s under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and Related Materials and is the directresponsibility of Subcommittee E01.03 on Precious Metals.Current edition approved Oct. 1, 2005. Published December 2005. Originallyapproved in 1992. Last previous edition ap
13、proved in 1997 as E 1446 92 (1997)e 1.2For 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 website.3Withdrawn.1Copyright A
14、STM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.sample testing. Alternative wavelengths, if shown to be free ofinterferences, may also be used.7. Apparatus7.1 D-C Argon Plasma Optical Emission SpectrometerThe instrument must be equipped with a s
15、ample nebulizationsystem compatible with mineral acids and with test solutionscontaining 4 % total solids. Follow the manufacturers instruc-tions for installation and operation.8. Reagents and Materials8.1 ArgonPurity: 99.998 % minimum.8.2 Copper Standard Solution (1 mL = 1.0 mg Cu)Transfer 1.000 g
16、of copper metal (purity: 99.9 % minimum) toa 400-mL beaker. Add 60 mL of HNO3(1+1) in 10-mLincrements and heat gently on a hot plate. When dissolution iscomplete, cool, then transfer to a 1-L volumetric flask. Diluteto volume with HNO3(1+99) and mix. This solution is stablefor at least six months.8.
17、3 Iron Standard Solution (1 mL = 1.0 mg Fe)Transfer1.000 g of iron metal (purity: 99.9 % minimum) to a 400-mLbeaker. Add 50 mL of HCl plus HNO3(4+1) and heat gently ona hot plate. When dissolution is complete, cool and thentransfer to a 1-L volumetric flask. Dilute to volume with HCL(1+99) and mix.
18、This solution is stable for six months.8.4 Lead Standard Solution (1 mL = 1.0 mg Pb)Transfer1.000 g of lead metal (purity: 99.9 % minimum) to a 400-mLbeaker. Add 50 mL of HNO3(1+4) and heat gently on hot plateto dissolve and then cool. Transfer the lead solution to a 1-Lvolumetric flask, dilute to v
19、olume with water, and mix. Thissolution is stable for six months.8.5 Matrix GoldGold purity must be a minimum99.9999 % based on total metallic impurities.8.6 Palladium Standard Solution (1 mL = 1.0 mg Pd)Transfer 1.000 g of palladium metal (purity: 99.9 % minimum)to a 400-mL beaker. Add 50 mL of HCl
20、 plus HNO3(4+1) andheat gently on a hot plate. When dissolution is complete, cool,then transfer to a 1-L volumetric flask and dilute to volumewith HCl (1+99) and mix. This solution is stable for sixmonths.8.7 Silver Standard Solution (1 mL = 1.0 mg Ag)Transfer1.000 g of silver metal (purity: 99.9 %
21、minimum) to a 400-mLbeaker. Add 60 mL of HNO3(1+1) and heat gently on a hotplate. When dissolution is complete, cool, then transfer to a 1-Lvolumetric flask, dilute to volume with HNO3(1+99), and mix.This solution should be stored in an amber glass container or inthe dark. This solution is stable fo
22、r at least six months. Anychlorides must be kept away from this solution or the silverwill be precipitated.9. Hazards9.1 For precautions to be observed in the use of certainreagents and equipment, refer to Practices E50.9.2 The ultraviolet radiation from the plasma must beshielded at all times to pr
23、event eye damage.9.3 All dissolution by acids must be performed under a hoodwith proper ventilation.10. Sampling10.1 For appropriate procedures on sampling the materialscovered by this test method, refer to Specification B 562.11. Interlaboratory Studies11.1 This test method was evaluated in accorda
24、nce withPractice E 173. Practice E 173 has been replaced by PracticeE 1601. The Reproducibility Index, R2of Practice E 173corresponds to the Reproducibility Index R of Practice E 1601.Likewise the Repeatability Index R1of Practice E 173 corre-sponds to Repeatability Index r of Practice E 1601.12. Ca
25、libration12.1 Calibration Solutions:12.1.1 Master Analyte SolutionClean a 100-mL volumet-ric flask by boiling with 10 mL of HCl (1+1) for 10 min andrinsing with water. Add 30 mL of HCl and transfer by meansof a pipet the amounts of standard solutions listed in Table 1.Dilute to the mark and mix. Sil
26、ver will not precipitate as silverchloride because of the presence of excess HCl. This solutionis stable for no longer than five days.12.1.2 High Calibration SolutionWeigh 2.000 6 0.003 gof matrix gold and transfer to a 50-mL volumetric flask,previously cleaned by boiling with HCl (1+1) for 10 min a
27、ndrinsing with water. Add 15 mL of HCl plus HNO3(4+1) andheat gently until dissolved. If the gold does not completelydissolve, add 10 mL of HCl plus HNO3(4+1) and heat gently tocomplete dissolution. Cool, then transfer by pipet 10 mL ofmaster analyte solution and dilute to volume with HCl (1+2),and
28、mix. This solution is equivalent to 300 ppm copper, 100ppm iron, 100 ppm lead, 300 ppm palladium, and 500 ppmsilver in the matrix gold.12.1.3 Medium Calibration SolutionWeigh 2.000 60.003 g of matrix gold and transfer to a 50-mL volumetricflask, previously cleaned by boiling with HCl (1+1) for 10 mi
29、nand rinsing with water. Add 15 mL of HCl plus HNO3(4+1)and heat gently until dissolved. If the gold does not dissolvecompletely, add 10 mLof HCl plus HNO3(4+1) and heat gentlyto complete dissolution. Cool, then transfer by pipet 5 mL ofthe master analyte solution and dilute to volume with HCl(1+2),
30、 and mix. This solution is equivalent to 150 ppm copper;50 ppm iron; 50 ppm lead; 150 ppm palladium; and 250 ppmsilver in the matrix gold.12.1.4 Low Calibration SolutionWeigh 2.000 6 0.003g of matrix gold and transfer to a 50-mL volumetric flask,previously cleaned by boiling with HCl (1+1) for 10 mi
31、n andrinsing with water. Add 15 mL of HCl plus HNO3(4+1)solution and heat gently until dissolved. If the gold does notcompletely dissolve, add 10 mL of HCl plus HNO3(4+1) andTABLE 1 Master Analyte SolutionElement Standard Solution, mLMaster Analyte Solution FinalConcentration, g/mLCopper 6 60Iron 2
32、20Lead 2 20Palladium 6 60Silver 10 100E1446052heat gently to complete dissolution. Cool, then transfer by pipet1 mL of master analyte solution and dilute to volume with HCl(1+2), and mix. This solution is equivalent to 30 ppm copper;10 ppm iron; 10 ppm lead; 30 ppm palladium; and 50 ppmsilver in the
33、 matrix gold.12.1.5 Blank Calibration SolutionWeigh 2.000 6 0.003 gof matrix gold and transfer to a 50-mL volumetric flask,previously cleaned by boiling with HCl (1+1) for 10 min andrinsing with water. Add 15 mL of HCl plus HNO3(4+1)solution and heat gently until dissolved. If the gold does notcompl
34、etely dissolve, add 10 mL of HCl plus HNO3(4+1) andheat gently to complete dissolution. Cool and dilute to volumewith HCl (1+2) and mix. This solution is equivalent to 0 ppmcopper; 0 ppm iron; 0 ppm lead; 0 ppm palladium; and 0 ppmsilver in the matrix gold.12.2 Instrument OptimizationAdjust all inst
35、rumental pa-rameters according to the instrument manufacturers recom-mended operating practices. Use the high calibration solutionwhen aligning optics and entrance slit positions. The elementemission wavelengths given in Table 2 have been shown to belinear and interference-free for refined gold matr
36、ices.12.3 Instrument CalibrationFollowing the instrumentmanufacturers instructions, calibrate the spectrometer usingthe low-calibration solution and the high-calibration solution atthe wavelengths listed in 12.2 and using three, 8-s integrations.If the instrument will only accept a high standard and
37、 a blank,use the high-calibration solution and the blank calibrationsolution. Rinse the aspiration system with HCl (1+2) for atleast 15 s between calibration solutions.12.4 Calibration VerificationAnalyze the high, low, orblank and medium calibration solutions using the instrumentmanufacturers recom
38、mended procedure. If all values are notwithin 5 % of the expected value, repeat the calibrationprocedure.13. Procedure13.1 Test Solution:13.1.1 Weigh 1.000 6 0.001 g of the sample and transfer toa 25-mL volumetric flask, previously cleaned by boiling withHCl (1+1) for 10 min and rinsing with water.A
39、dd 7 mL of HClplus HNO3(4+1) and heat gently until dissolved. If the sampledoes not completely dissolve or silver chloride is seen as aprecipitate, add 5 mL of HCl plus HNO3(4+1) and heat gentlyto complete the dissolution. Cool, then dilute to volume withHCl (1+2), and mix.13.1.2 For the determinati
40、on of each element, aspirate thetest solution and record its concentration, using the instrumentmanufacturers recommended procedure. Verify the calibrationafter every four sample determinations. If the measured valuesfor the calibration solutions are not within 5 % of expectedvalues, repeat the cali
41、bration procedure and the sample mea-surement. Aspirate HCl (1+2) for at least 15 s after each test orcalibration solution.13.1.3 As an alternative to verifying calibration, the driftcorrection procedure as described in Guide E 1097 may beused.14. Calculation14.1 This test method is designed so that
42、 direct readinginstruments will provide results in parts per million weightconcentration in the refined gold sample material.15. Precision and Bias15.1 Precision4This test method was tested in an inter-laboratory testing program with seven participating laborato-ries. Three samples were tested for t
43、he determination of silver,palladium, and lead, and four samples were tested for thedetermination of iron. The results are summarized in Table 3.15.2 BiasNo information on the accuracy of this testmethod is known because at the time it was tested, no certifiedreference materials were available. User
44、s are encouraged toemploy suitable reference materials if available to verify theaccuracy of the method in their laboratory.16. Keywords16.1 direct current argon plasma spectroscopy; gold;spectrometry4Supporting data are available from ASTM International Headquarters. RequestRR: E010300.TABLE 2 Elem
45、ent Emission WavelengthsElement Wavelength, nm Alternate Wavelength, nmCopper 327.3 324.7Iron 259.9 .Lead 405.7 .Palladium 340.4 .Silver 328.0 338.3TABLE 3 Statistical InformationElement SampleTest Mean,ppmAr, ppmAR, ppmACopper 1A 111.2 3.83 6.302A 311.4 7.73 8.563A 8.0 0.95 1.08Iron 1A 4.1 0.93 1.5
46、32A 4.3 0.49 1.313A 2.4 0.82 1.224A 141.3 2.40 6.81Lead 1A 31.2 0.78 1.492A 72.1 2.84 3.293A 18.8 0.67 1.33Palladium 1A 339.1 10.97 15.832A 106.9 3.93 4.573A 12.4 0.65 0.83Silver 1A 19.5 1.47 1.592A 228.7 5.14 9.903A 519.3 8.19 25.48ATo convert parts per million (ppm) to percent (%), divide the ppm
47、value by10 000 and report in accordance with Practice E29.E1446053ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any s
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