1、Designation: E 1097 03Standard Guide forDirect Current Plasma Emission Spectrometry Analysis1This 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 revision. A n
2、umber 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 currentargon plasma atomic emission spectrometer (DCP) to deter-mine the concentration
3、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 does
4、 not specify all the operating conditionsfor a DCP because of the differences between models of theseinstruments. Analysts should follow instructions provided bythe manufacturer of the particular instrument.1.3 This guide does not attempt to specify in detail all of thehardware components and comput
5、er 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 purport t
6、o 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 given in Se
7、ction 8.2. Referenced Documents2.1 ASTM Standards:2E 29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE 50 Practices for Apparatus, Reagents, and Safety Precau-tions for Chemical Analysis of Metals, Ores, and RelatedMaterialsE 135 Terminology Relating
8、to Analytical Chemistry forMetals, Ores, and Related MaterialsE 743 Guide for Spectrochemical Laboratory Quality As-surance3E 876 Practice for Use of Statistics in the Evaluation ofSpectrometric DataE 882 Guide for Accountability and Quality Control in theChemical Analysis LaboratoryE 1601 Practice
9、for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical MethodE 1832 Practice for Describing and Specifying a DirectCurrent Plasma Atomic Emission Spectrometer3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this guide, refer toTerminology E 135.3.2 De
10、finitions of Terms Specific to this Guide:3.2.1 background equivalent concentration (BEC), ntheanalyte concentration whose signal is equivalent to the signalgenerated by the plasma and matrix at the analyte line when theactual analyte concentration is zero.3.2.2 detection limit (DL), nthe smallest q
11、uantity detect-able by the DCP.3.2.2.1 approximate detection limit (ADL), nan estimateddetection limit calculated from the background equivalentconcentration.3.2.2.2 instrumental detection limit (IDL), nFor DCPplasma, the analyte concentration corresponding to three timesthe standard deviation of th
12、e background noise beneath theanalyte line on a set of nine consecutive 10-s measurements ofthe background intensity of the blank.3.2.2.3 method detection limit (MDL), nthe detectionlimit measured on the matrix blank.3.2.3 equivalent analyte concentration, nthe apparentconcentration of an interferin
13、g element on an analyte.3.2.4 interference, nany chemical, physical, or spectraleffect that changes the apparent net emission intensity from aspectral line other than a change in concentration of theelement emitting that spectral line.3.2.5 linear dynamic range, nthe concentration rangefrom the quan
14、tifiable limit to the highest concentration thatremains within 6 10 % of linearity based on lower concentra-tions.1This guide is under the jurisdiction of ASTM Committee E01 on AnalyticalChemistry for Metals, Ores, and Related Materials and is the direct responsibility ofSubcommittee E01.20 on Gener
15、al Analytical Practices.Current edition approved Oct. 1, 2003. Published Dec. 2003. Originallypublished as E-3 Proposal P152. Last previous edition approved in 1997 asE 1097 97.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. F
16、or Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.6 order, spectral, nthe number of wavelength differ-en
17、ces between reflections from successive grooves of a gratingor echelle; typically one or two wavelengths for the first orsecond orders of a grating, 50 or 51 wavelengths for the fiftiethand fifty-first orders from an echelle.3.2.6.1 DiscussionIn the DCP echelle, a number of wave-lengths appear in tw
18、o adjacent orders, and these wavelengthsusually have similar intensities.3.2.7 quantifiable limit (QL)the lowest concentration atwhich the instrument can measure reliably with a defined errorand confidence level.3.2.8 sensitivitythe slope of the analytical curve, which isthe ratio of the change in e
19、mission intensity to the change inconcentration.4. Summary of Guide4.1 Direct current argon plasma atomic emission spectrom-eters, either simultaneous or sequential, measure elements insolution using atomic emission. Samples and calibration solu-tions are nebulized and the aerosol is transported to
20、the directcurrent plasma jet where excitation occurs and characteristicemission spectra are produced. The spectra are dispersed by anechelle grating and cross-dispersed by a prism or grating. Theyimpinge on photomultiplier tubes, whose outputs are inter-preted by a computer as emission intensities.
21、Backgroundcorrection can be used to compensate for some interferences.The computer generates calibration curves and calculatesanalyte concentration.5. Significance and Use5.1 Analyses using direct current plasma spectrometry re-quire proper preparation of test solutions, accurate calibration,and con
22、trol of analytical procedures. ASTM test methods thatrefer to this guide shall provide specifics on test solutions,calibration, and procedures.5.2 Direct current plasma analysis is primarily concernedwith testing materials for compliance with specifications, butmay range from qualitative estimations
23、 to umpire analysis.These may involve measuring major and minor constituents ortrace impurities, or both. This guide suggests some approachesto these 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 trainedana
24、lysts capable of performing common 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 d-c plasma analysis. Ana-lysts should ensure t
25、hat proper quality assurance proceduresare followed, especially those defined by the test method. Referto Guides E 743 and E 882 or the USEPA Contract LaboratoryProgram.46. Preparation of Solutions6.1 Solutions are prepared for different purposes. Not allmay be necessary for every test. Prepare only
26、 those directed bythe method or required to meet specific experimental objec-tives.6.2 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
27、 sample introductionsystem between each determination of calibration solutions andtest 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 ta
28、king a reading.6.3 Reagent Blank SolutionThis solution consists of allreagents and other 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 composit
29、ion to the test solution as possible (includingdissolution reagents and matrix elements), but omitting theelements to be determined. The matrix elements should be ofhigh purity.6.5 ControlSelect a reference material, certified referencematerial, or other material of known composition and prepareit a
30、s directed in the test method. This control solution may beused to verify the initial calibration. Analyze the controlregularly as a blind sample and use the results for qualitycontrol as directed in Guide E 882.6.6 Calibration SolutionsThe number and type of thesesolutions will depend on the method
31、, and on the type of plasmainstrument and its microprocessor. Generally, prepare twoinstrument calibration solutions, one high concentration, andone low concentration or a blank, that bracket the expectedconcentration range of the sample test solutions. Also prepareat least one other intermediate ca
32、libration solution. More maybe prepared if the microprocessor can utilize them, especiallyif the analyte composition of the test solutions is expected tocover a wide range or if the calibration curve is non-linear.Prepare the calibration solutions by adding aliquots from stocksolutions to solutions
33、that are similar to the matrix of the testsample.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 elements are present. Some matrix elements may beeliminated if i
34、t 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 thecomposition of the test solution is unknown to the extent thatmatche
35、d matrix 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 lowconcentration calibration solution, prepare it the same way as the highc
36、oncentration calibration solution is prepared, omitting the elements to bedetermined. Where matched matrix calibration solutions are employed,4USEPA Contract Laboratory Program Statement of Work for InorganicAnalysis, Multi-Media, Multi-Concentration, SOW 7/88, Sample ManagementOffice, P.O. Box 818,
37、 Alexandria, VA 22313, 1988.E1097032this will be the matrix blank solution.6.6.2 Optimum Calibration Solution ConcentrationRangeFor 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 acc
38、epts alow concentration calibration solution, its concentration shouldbe at least four times the method detection limit and above thequantifiable limit.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. Toa
39、ll 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 concentration ofthe analyte(s) in the test solution. The original analyte concen-tration must be at or above its quantifiable limit. The finalanalyte concentration in the highest spike must
40、 not be greaterthan the linear range of the emission line used. Dilute allsolutions to the mark and mix. Prepare an equal volume of thereagent blank 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 knownamo
41、unts of the analyte equal to 0.5, 1.0, and 1.5 or 1.0, 2.0, and3.0 times the expected concentration of the analyte(s) in thetest solution. The final analyte concentration in the test solutionshould be at or above the quantifiable limit. The final analyteconcentration in the highest spike should not
42、exceed the lineardynamic range of the emission line used. Dilute all solutions tothe mark and mix. Prepare an equal volume of the reagentblank solution if using 10.6.2. Multiply the final value by afactor to compensate for dilution.6.8 Calibration Verification SolutionPrepare a solutionwhose concent
43、ration is in the midrange in the calibration curve.This may be one of the calibration solutions.6.9 Spike Recovery SamplePrepare a test solution asdirected in the method. Add a spike of the analyte(s) equal toat least 5 times each analytes quantifiable limit.6.10 Quantifiable Limit SolutionPrepare a
44、 solution con-taining amounts of analyte three to six times the methoddetection limit or 10 to 20 % of the BEC and matched asclosely to the matrix as possible.7. Hazards7.1 Protect eyes from the intense ultraviolet (UV) radiationof the plasma.7.2 Follow the manufacturers recommended operatingpractic
45、es for igniting the plasma and operating the instrument.7.3 Ensure that HF-resistant materials are used when ana-lyzing 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 Pract
46、ices E 50.8. Characterization of Analytical Lines8.1 Overview:8.1.1 When setting up a new method, use the recommenda-tions in this section to select a wavelength and evaluate thepossible interferences. Measure the approximate linear range,background equivalent concentration, sensitivity, and detecti
47、onlimit experimentally, and ascertain that they are adequate forthe analysis. Once these have been established for a specificinstrument, periodic confirmation is recommended and espe-cially whenever a change is made in the hardware (forexample, transport or detection devices) or optics. Confirm byan
48、alysis of controls or quantifiable limit measurements, orboth, that the daily performance of the instrument meets thecriteria of the method.8.1.2 When using an established method for the first time,confirm that freedom from interferences, linearity, detectionlimit, and sensitivity meet the criteria
49、of the method.8.1.3 For information on wavelengths, refer to Bosshart,5Harrison,6or Winge7.8.2 InterferencesSeveral 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 emissionlines, or high concentrations of easily ionized elements. Thepresence of interferences should be considered when selectingcalibration solutions and the method of analysis. See 8.2.3 forsuggestions on how to compensate for interference
