1、Designation: E 1097 07Standard Guide forDirect Current Plasma-Atomic Emission SpectrometryAnalysis1This standard is issued under the fixed designation E 1097; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisio
2、n. 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 guide covers procedures for using a direct currentplasma-atomic emission spectrometer (DCP-AES) to deter-mine the concentrat
3、ion of elements in solution. Recommenda-tions are provided for preparing and calibrating the instrument,assessing instrument performance, diagnosing and correctingfor interferences, measuring test solutions, and calculatingresults. A method to correct for instrument drift is included.1.2 This guide
4、does not specify all the operating conditionsfor a DCP-AES because of the differences between models ofthese instruments. Analysts should follow instructions pro-vided by the manufacturer of the particular instrument.1.3 This guide does not attempt to specify in detail all of thehardware components
5、and computer software of the instru-ment. It is assumed that the instrument, whether commerciallyavailable, modified, or custom built, will be capable of per-forming the analyses for which it is intended, and that theanalyst has verified this before performing the analysis.1.4 This standard does not
6、 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. Specific precau-tionary statements are g
7、iven in Section 7.2. Referenced Documents2.1 ASTM Standards:2E29 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 MaterialsE 135 Terminolog
8、y Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE 882 Guide for Accountability and Quality Control in theChemical Analysis LaboratoryE 1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method3. Terminology3.1 Definitions: For d
9、efinitions of terms used in this guide,refer to Terminology E 135.3.2 Definitions of Terms Specific to This Standard:3.2.1 background equivalent concentration (BEC), ninDCP-AES, the analyte concentration whose signal is equivalentto the signal generated by the plasm and matrix at the analyteline whe
10、n the actual analyte concentration is zero.3.2.2 detection limit (DL), nin addition to the DL definedin Terminology E 135, the following detection limits aredescribed and used in this guide:3.2.2.1 instrumental detection limit (IDL), nin DCP-AES,the analyte concentration corresponding to three times
11、 thestandard deviation of the background noise beneath the analyteline on a set of nine consecutive 10-s measurements of thebackground intensity of the blank.3.2.2.2 method detection limit (MDL), nin DCP-AES, thedetection limit measured on the matrix blank.3.2.3 equivalent analyte concentration, nth
12、e apparentconcentration of an interfering element on an anlalyte.3.2.4 linear dynamic range, nthe concentration rangefrom the limit of quantification to the highest concentration thatremains within 610 % of linearity based on lower concentra-tions.3.2.5 limit of quantification (LOQ), nthe lowest con
13、cen-tration at which the instrument can measure reliably with adefined error and confidence level.3.2.6 sensitivity, nthe slope of the analytical curve, whichis the ratio of the change in emission intensity to the change inconcentration.4. Summary of Guide4.1 Direct current plasma-atomic emission sp
14、ectrometers,either simultaneous or sequential, measure the concentration ofelements in solution. Samples, calibration and other solutionsare nebulized and the aerosol is transported to the direct currentplasma jet where excitation occurs and characteristic emission1This guide is under the jurisdicti
15、on of ASTM Committee E01 on AnalyticalChemistry for Metals, Ores and Related Materials and is the direct responsibility ofSubcommittee E01.20 on Fundamental Practices.Current edition approved Nov. 1, 2007. Published November 2007. Originallyapproved in 1986. Last previous edition approved in 2003 as
16、 E 1097 03.2For 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.1Copyright ASTM International, 100 Barr Harbor Dri
17、ve, PO Box C700, West Conshohocken, PA 19428-2959, United States.spectra are produced. The spectra are dispersed by an echellegrating and cross-dispersed by a prism or grating. The spectrathen impinge on photomultiplier tubes, whose outputs areinterpreted by a microprocessor/PC as emission intensiti
18、es.Background correction can be used to compensate for someinterferences. The microprocessor/PC generates calibrationcurves and calculates analyte concentration.5. Significance and Use5.1 Analyses using DCP-AES require proper preparation oftest solutions, accurate calibration, and control of analyti
19、calprocedures. ASTM test methods that refer to this guide shallprovide specifics on test solutions, calibration, and procedures.5.2 DCP-AES analysis is primarily concerned with testingmaterials for compliance with specifications, but may rangefrom qualitative estimations to umpire analysis. These ma
20、yinvolve measuring major and minor constituents or traceimpurities, or both. This guide suggests some approaches tothese different analytical needs.5.3 This guide assists analysts in developing new methods.5.4 It is assumed that the users of this guide will be trainedanalysts capable of performing c
21、ommon laboratory proceduresskillfully and safely. It is expected that the work will beperformed in a properly equipped laboratory.5.5 This guide does not purport to define all of the qualityassurance parameters necessary for DCP-AES analysis. Ana-lysts should ensure that proper quality assurance pro
22、ceduresare followed, especially those defined by the test method. Referto Guide E 882.6. Preparation of Solutions6.1 Solutions are prepared for different purposes. Not allmay be necessary for every test. Prepare only those directed bythe method or required to meet specific experimental objec-tives.6
23、.2 Rinse SolutionPrepare a rinse solution to contain theacids or bases present in the test solution at the sameconcentration. Prepare a quantity sufficient to clean the end ofthe sample uptake tubing and to flush the sample introductionsystem between each determination of calibration solutions andte
24、st solutions. Occasionally, an analyte requires a conditioningtime in the aspiration/nebulization system of the instrument. Inthis case, use the test solution as a rinse and allow a sufficientresidence time before taking a reading.6.3 Reagent Blank SolutionThis solution consists of allreagents and o
25、ther additions at the same concentration used inpreparing the test solution. Carry this solution through theentire sample preparation procedure.6.4 Matrix Blank SolutionPrepare this solution to be asclose in composition to the test solution as possible (includingdissolution reagents and matrix eleme
26、nts), but omitting theelements to be determined. The matrix elements should be ofhigh purity.6.5 ControlSelect a reference material or other material ofknown composition and prepare it as directed in the testmethod. Analyze the control regularly as a blind sample anduse the results for quality contr
27、ol as directed in Guide E 882.6.6 Calibration SolutionsThe number and type of thesesolutions will depend on the method, and on the type ofDCP-AES instrument and its microprocessor/PC. Generally,prepare two instrument calibration solutions, one high concen-tration, and one low concentration or a blan
28、k, that bracket theexpected concentration range of the sample test solutions.More may be prepared if the microprocessor/PC can utilizethem, especially if the analyte composition of the test solutionsis expected to cover a wide range or if the calibration curve isnon-linear. Prepare the calibration s
29、olutions by adding aliquotsfrom stock solutions to solutions that are similar to the matrixof the test sample.6.6.1 Match the matrix of the calibration solutions asclosely as possible to that of the test solution in acidity, totalsolids, reagents, and matrix elements, especially if easilyionized ele
30、ments (EIE) are present. Some matrix elements maybe eliminated if it can be shown by spike addition or standardadditions that the effect on the test solution analytes isinsignificant. Use stock solutions or pure elements prepared bya method similar to that used to prepare the test solutions. If thec
31、omposition of the test solution is unknown to the extent thatmatrix-matched solutions cannot be prepared, or if a suffi-ciently pure matrix material is not available, refer to themethod of standard additions described in 6.7 and 10.6.NOTE 1If the instrument is designed to use a blank as the lowconce
32、ntration calibration solution, prepare it the same way as the highconcentration calibration solution is prepared, omitting the elements to bedetermined. Where matrix-matched calibration solutions are employed,this will be the matrix blank solution.6.6.2 Optimum Calibration Solution ConcentrationRang
33、eFor calibration in the linear range, the highest con-centration should be no more than 85 % of the upper limit ofthe calibration curve linearity. For an instrument that accepts alow concentration calibration solution, its concentration shouldbe at least four times the method detection limit and abo
34、ve thelimit of quantification (LOQ).6.7 Standard Additions SolutionsPrepare as directed ineither 6.7.1 or 6.7.2 as follows:6.7.1 Prepare four separate test solutions of the sample. Toall but one, add known amounts of the analyte equal to 0.5, 1.0,and 1.5, or 1.0, 2.0, and 3.0 times the expected conc
35、entration ofthe analyte(s) in the test solution. The original analyte concen-tration must be at or above its LOQ. The final analyteconcentration in the highest spike must not be greater than thelinear range of the emission line used. Dilute all solutions tothe mark and mix. Prepare an equal volume o
36、f the reagentblank solution when using 10.6.2.6.7.2 Transfer four equal volumes of a test solution to fourvolumetric flasks of the same size. To all but one, add knownamounts of the analyte equal to 0.5, 1.0, and 1.5, or 1.0, 2.0,and 3.0 times the expected concentration of the analyte(s) inthe test
37、solution. The final analyte concentration in the testsolution should be at or above the LOQ. The final analyteconcentration in the highest spike should not exceed the lineardynamic range of the emission line used. Dilute all solutions tothe mark and mix. Prepare an equal volume of the reagentblank s
38、olution if using 10.6.2. Multiply the final value by afactor to compensate for dilution.E10970726.8 Calibration Verification SolutionTo verify the calibra-tion, prepare one or more solutions whose concentrations arebetween the highest concentration calibration solution and theLOQ.6.9 Spike Recovery
39、SamplePrepare a test solution asdirected in the method. Add a spike of the analyte(s) equal toat least 5 times each analytes LOQ.6.10 Limit of Quantification (LOQ) SolutionPrepare asolution containing amounts of analyte three to six times themethod detection limit or 10 to 20 % of the BEC and matche
40、das closely to the matrix as possible.7. Hazards7.1 Protect eyes from the intense ultraviolet (UV) radiationof the plasma.7.2 Follow the manufacturers recommended operatingpractices for initiating the plasma and operating the instrument.7.3 Ensure that HF-resistant materials are used when ana-lyzing
41、 solutions containing hydrofluoric acid. Avoid stronglycaustic solutions that may cause the ceramic sleeves of theelectrodes to fuse.7.4 For other safety precautions, refer to Practice E50.8. Characterization of Analytical Lines8.1 Overview:8.1.1 When researching a new method, use the recommen-datio
42、ns in this section to select a wavelength and evaluate thepossible interferences. Measure the approximate linear range,background equivalent concentration, sensitivity, LOQ detec-tion limit experimentally, and ascertain that they are adequatefor the analysis. Once these have been established for a s
43、pecificinstrument, periodic confirmation is recommended and espe-cially whenever a change is made in the hardware (forexample, transport or detection devices) or optics. Confirm byanalysis of controls, including limit of quantification measure-ments when required, that the daily performance of thein
44、strument meets the criteria of the method.8.1.2 When adapting a documented test method for the firsttime, confirm that freedom from interferences, linearity, detec-tion limit, LOQ and sensitivity meet the criteria of the method.8.1.3 For lists of wavelengths and information on theircharacteristics,
45、refer to Harrison,3Meggers,4Phelps,5Reader,6or Winge.78.1.3.1 In the laddered array of spectra from the DCPsechelle grating, some wavelengths appear in two adjacentorders. These wavelengths usually have similar intensities.Occasionally, one may prove more useful for a specificapplication.8.2 Interfe
46、rencesSeveral types of interferences may affectmeasurements. This is especially true for test solutions con-taining high concentrations of solids or acids or containingelements having intense emission, a large number of atomicemission lines, or high concentrations of easily ionized ele-ments (EIEs).
47、 The presence of interferences should be consid-ered when selecting calibration solutions and the method ofanalysis. See 8.2.3 for suggestions on how to compensate forinterferences.8.2.1 Types of Interference:8.2.1.1 Chemical InterferencesEffects from excitation,molecular compound formation, and sol
48、vent vaporization.8.2.1.2 Physical InterferencesFactors that change the rateof sample delivery such as viscosity, surface tension, andreaction with parts of the sample delivery system.8.2.1.3 Spectral InterferencesSpectral line or molecularband overlap from the matrix or solvents, background resulti
49、ngfrom continuum radiation, or stray light.8.2.2 Diagnosis of InterferencesUse the following proce-dures for each new sample matrix:8.2.2.1 Comparison with Alternative Method(s) ofAnalysisUse established methods to compare analyticalresults where possible.8.2.2.2 Wavelength ScanningIf possible, scan the wave-length region near the analyte emission to detect spectralinterferences and high background in calibration solutions, testsolutions, and solutions containing suspected interfering ele-ments.8.2.2.3 Spike RecoveryAdd a known quantity or spike ofthe an
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