ASTM E1097-2012 Standard Guide for Determination of Various Elements by Direct Current Plasma Atomic Emission Spectrometry 《使用直流等离子体原子发射光谱法测定各种元素的标准指南》.pdf

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1、Designation:E109707 Designation: E1097 12Standard Guide forDirect Current Plasma-Atomic Emission SpectrometryAnalysisDetermination of Various Elements by DirectCurrent Plasma Atomic Emission Spectrometry1This standard is issued under the fixed designation E1097; the number immediately following the

2、designation indicates 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers procedur

3、es for using a direct current plasma-atomicDirect Current Plasma atomic emission spectrometer(DCP-AES) to determine the concentration of elements in solution. Recommendations are provided for preparing and calibratingthe instrument, assessing instrument performance, diagnosing and correcting for int

4、erferences, measuring test solutions, andcalculating results. A method to correct for instrument drift is included.1.2 This guide does not specify all the operating conditions for a DCP-AES because of the differences between models of theseinstruments. Analysts should follow instructions provided by

5、 the manufacturer of the particular instrument.1.3 This guide does not attempt to specify in detail all of the hardware components and computer software of the instrument.It is assumed that the instrument, whether commercially available, modified, or custom built, will be capable of performing thean

6、alyses for which it is intended, and that the analyst has verified this before performing the analysis.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and h

7、ealth practices and determine the applicability of regulatorylimitations prior to use. Specific precautionary statements are given in Section 7.2. Referenced Documents2.1 ASTM Standards:2E29 Practice for Using Significant Digits in Test Data to Determine Conformance with SpecificationsE50 Practices

8、forApparatus, Reagents, and Safety Considerations for ChemicalAnalysis of Metals, Ores, and Related MaterialsE135 Terminology Relating to Analytical Chemistry for Metals, Ores, and Related MaterialsE882 Guide for Accountability and Quality Control in the Chemical Analysis LaboratoryE1601 Practice fo

9、r Conducting an Interlaboratory Study to Evaluate the Performance of an Analytical Method3. Terminology3.1 Definitions: For definitions of terms used in this guide, refer to Terminology E135.3.2 Definitions of Terms Specific to This Standard:3.2.1 background equivalent concentration (BEC), nin DCP-A

10、ES, the analyte concentration whose signal is equivalent to thesignal generated by the plasma and matrix at the analyte line when the actual analyte concentration is zero.3.2.2 detection limit (DL), nin addition to the DL defined in Terminology E135, the following detection limits are describedand u

11、sed in this guide:3.2.2.1 instrumental detection limit (IDL), nin DCP-AES, the analyte concentration corresponding to three times the standarddeviation of the background noise beneath the analyte line on a set of nine consecutive 10-s measurements of the backgroundintensity of the blank.3.2.2.2 meth

12、od detection limit (MDL), n in DCP-AES, the detection limit measured on the matrix blank.3.2.3 equivalent analyte concentration, nthe apparent concentration of an interfering element on an anlalyte.3.2.4 linear dynamic range, nthe concentration range from the limit of quantification to the highest c

13、oncentration that remainswithin 610 % of linearity based on lower concentrations.1This guide is under the jurisdiction of ASTM Committee E01 on Analytical Chemistry for Metals, Ores, and Related Materials and is the direct responsibility ofSubcommittee E01.20 on Fundamental Practices.Current edition

14、 approved Nov.June 1, 2007.2012. Published November 2007.June 2012. Originally approved in 1986. Last previous edition approved in 20032007 asE1097 037. DOI: 10.1520/E1097-07.10.1520/E1097-12.2For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at servi

15、ceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version.

16、Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 1

17、00 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.5 limit of quantification (LOQ), nthe lowest concentration at which the instrument can measure reliably with a definederror and confidence level.3.2.6 sensitivity, nthe slope of the analytical curve, which is the

18、ratio of the change in emission intensity to the change inconcentration.4. Summary of Guide4.1 Direct current plasma-atomicCurrent Plasma atomic emission spectrometers, either simultaneous or sequential, measure theconcentration of elements in solution. Samples, calibration and other solutions are n

19、ebulized and the aerosol is transported to thedirect current plasma jet where excitation occurs and characteristic emission spectra are produced. The spectra are dispersed byan echelle grating and cross-dispersed by a prism or grating. The spectra then impinge on photomultiplier tubes, whose outputs

20、are interpreted by a microprocessor/PC as emission intensities. Background correction can be used to compensate for someinterferences. The microprocessor/PC generates calibration curves and calculates analyte concentration.5. Significance and Use5.1 Analyses using DCP-AES require proper preparation

21、of test solutions, accurate calibration, and control of analyticalprocedures. ASTM test methods that refer to this guide shall provide specifics on test solutions, calibration, and procedures.5.2 DCP-AES analysis is primarily concerned with testing materials for compliance with specifications, but m

22、ay range fromqualitative estimations to umpire analysis. These may involve measuring major and minor constituents or trace impurities, or both.This guide suggests some approaches to these different analytical needs.5.3 This guide assists analysts in developing new methods.5.4 It is assumed that the

23、users of this guide will be trained analysts capable of performing common laboratory proceduresskillfully and safely. It is expected that the work will be performed in a properly equipped laboratory.5.5 This guide does not purport to define all of the quality assurance parameters necessary for DCP-A

24、ES analysis. Analystsshould ensure that proper quality assurance procedures are followed, especially those defined by the test method. Refer to GuideE882.6. Preparation of Solutions6.1 Solutions are prepared for different purposes. Not all may be necessary for every test. Prepare only those directed

25、 by themethod or required to meet specific experimental objectives.6.2 Rinse SolutionPrepare a rinse solution to contain the acids or bases present in the test solution at the same concentration.Prepare a quantity sufficient to clean the end of the sample uptake tubing and to flush the sample introd

26、uction system between eachdetermination of calibration solutions and test solutions. Occasionally, an analyte requires a conditioning time in theaspiration/nebulization system of the instrument. In this case, use the test solution as a rinse and allow a sufficient residence timebefore taking a readi

27、ng.6.3 Reagent Blank SolutionThis solution consists of all reagents and other additions at the same concentration used inpreparing the test solution. Carry this solution through the entire sample preparation procedure.6.4 Matrix Blank SolutionPrepare this solution to be as close in composition to th

28、e test solution as possible (includingdissolution reagents and matrix elements), but omitting the elements to be determined. The matrix elements should be of highpurity.6.5 ControlSelect a reference material or other material of known composition and prepare it as directed in the test method.Analyze

29、 the control regularly as a blind sample and use the results for quality control as directed in Guide E882.6.6 Calibration SolutionsThe number and type of these solutions will depend on the method, and on the type of DCP-AESinstrument and its microprocessor/PC. Generally, prepare two instrument cali

30、bration solutions, one high concentration, and onelow concentration or a blank, that bracket the expected concentration range of the sample test solutions. More may be preparedif the microprocessor/PC can utilize them, especially if the analyte composition of the test solutions is expected to cover

31、a widerange or if the calibration curve is non-linear. Prepare the calibration solutions by adding aliquots from stock solutions to solutionsthat are similar to the matrix of the test sample.6.6.1 Match the matrix of the calibration solutions as closely as possible to that of the test solution in ac

32、idity, total solids,reagents, and matrix elements, especially if easily ionized elements (EIE) are present. Some matrix elements may be eliminatedif it can be shown by spike addition or standard additions that the effect on the test solution analytes is insignificant. Use stocksolutions or pure elem

33、ents prepared by a method similar to that used to prepare the test solutions. If the composition of the testsolution is unknown to the extent that matrix-matched solutions cannot be prepared, or if a sufficiently pure matrix material is notavailable, refer to the method of standard additions describ

34、ed in 6.7 and 10.6.NOTE 1If the instrument is designed to use a blank as the low concentration calibration solution, prepare it the same way as the high concentrationcalibration solution is prepared, omitting the elements to be determined. Where matrix-matched calibration solutions are employed, thi

35、s will be the matrixblank solution.6.6.2 Optimum Calibration Solution Concentration RangeFor calibration in the linear range, the highest concentration shouldbe no more than 85 % of the upper limit of the calibration curve linearity. For an instrument that accepts a low concentrationE1097 122calibra

36、tion solution, its concentration should be at least four times the method detection limit and above the limit of quantification(LOQ).6.7 Standard Additions SolutionsPrepare as directed in either 6.7.1 or 6.7.2 as follows:6.7.1 Prepare four separate test solutions of the sample. To all but one, add k

37、nown amounts of the analyte equal to (0.5, 1.0,and 1.5, 1.5) times or (1.0, 2.0, and 3.0) times the expected concentration of the analyte(s) in the test solution. The original analyteconcentration must be at or above its LOQ. The final analyte concentration in the highest spike must not be greater t

38、han the linearrange of the emission line used. Dilute all solutions to the mark and mix. Prepare an equal volume of the reagent blank solutionwhen using 10.6.2.6.7.2 Transfer four equal volumes of a test solution to four volumetric flasks of the same size. To all but one, add knownamounts of the ana

39、lyte 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) in the testsolution. The final analyte concentration in the test solution should be at or above the LOQ. The final analyte concentration in thehighest spike should not exceed the linear dynamic r

40、ange of the emission line used. Dilute all solutions to the mark and mix.Prepare an equal volume of the reagent blank solution if using 10.6.2. Multiply the final value by a factor to compensate fordilution.6.8 Calibration Verification SolutionTo verify the calibration, prepare one or more solutions

41、 whose concentrations arebetween the highest concentration calibration solution and the LOQ.6.9 Spike Recovery SamplePrepare a test solution as directed in the method. Add a spike of the analyte(s) equal to at least5 times each analytes LOQ.6.10 Limit of Quantification (LOQ) SolutionPrepare a soluti

42、on containing amounts of analyte three to six times the methoddetection limit or 10 % to 20 % of the BEC and matched as closely to the matrix as possible.7. Hazards7.1 Protect eyes from the intense ultraviolet (UV) radiation of the plasma.7.2 Follow the manufacturers recommended operating practices

43、for initiating the plasma and operating the instrument.7.3 Ensure that HF-resistant materials are used when analyzing solutions containing hydrofluoric acid. Avoid strongly causticsolutions that may cause the ceramic sleeves of the electrodes to fuse.7.4 For other safety precautions, refer to Practi

44、ce E50.8. Characterization of Analytical Lines8.1 Overview:8.1.1 When researching a new method, use the recommendations in this section to select a wavelength and evaluate the possibleinterferences. Measure the approximate linear range, background equivalent concentration, sensitivity, LOQ detection

45、 limitexperimentally, and ascertain that they are adequate for the analysis. Once these have been established for a specific instrument,periodic confirmation is recommended and especially whenever a change is made in the hardware (for example, transport ordetection devices) or optics. Confirm by ana

46、lysis of controls, including limit of quantification measurements when required, thatthe daily performance of the instrument meets the criteria of the method.8.1.2 When adapting a documented test method for the first time, confirm that freedom from interferences, linearity, detectionlimit, LOQ and s

47、ensitivity meet the criteria of the method.8.1.3 For lists of wavelengths and information on their characteristics, refer to Harrison,3Meggers,4Phelps,5Reader,6orWinge.78.1.3.1 In the laddered array of spectra from the DCPs echelle grating, some wavelengths appear in two adjacent orders. Thesewavele

48、ngths usually have similar intensities. Occasionally, one may prove more useful for a specific application.8.2 InterferencesSeveral types of interferences may affect measurements. This is especially true for test solutions containinghigh concentrations of solids or acids or containing elements havin

49、g intense emission, a large number of atomic emission lines,or high concentrations of easily ionized elements (EIEs). The presence of interferences should be considered when selectingcalibration solutions and the method of analysis. See 8.2.3 for suggestions on how to compensate for interferences.8.2.1 Types of Interference:8.2.1.1 Chemical InterferencesEffects from excitation, molecular compound formation, and solvent vaporization.8.2.1.2 Physical InterferencesFactors that change the rate of sample delivery such as viscosity, surface tension, and reaction