1、Designation: E2972 15Standard Guide forProduction, Testing, and Value Assignment of In-HouseReference Materials for Metals, Ores, and Other RelatedMaterials1This standard is issued under the fixed designation E2972; the number immediately following the designation indicates the year oforiginal adopt
2、ion 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 document provides guidance for the implementa-tion of procedures for
3、 preparation of in-house reference mate-rials for analytical testing of metals, ores, slags, and othermaterials encountered within the metals and mining industries.1.2 This guide is applicable to the production of referencematerials only (usually for internal use) and does not apply tothe production
4、 of certified reference materials (CRMs). Mate-rials may include metals, alloys, minerals, geological materials,manufacturing intermediates, and byproducts. Samples may bein a number of physical forms including blocks, disks, rods,wires, chips, granules, powders, and liquids.1.3 This standard does n
5、ot 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. Referenced Documents2.1 ASTM Standar
6、ds:2E32 Practices for Sampling Ferroalloys and Steel Additivesfor Determination of Chemical Composition (Withdrawn2015)3E34 Test Methods for Chemical Analysis of Aluminum andAluminum-Base AlloysE50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, a
7、ndRelated MaterialsE55 Practice for Sampling Wrought Nonferrous Metals andAlloys for Determination of Chemical CompositionE88 Practice for Sampling Nonferrous Metals and Alloys inCast Form for Determination of Chemical CompositionE135 Terminology Relating to Analytical Chemistry forMetals, Ores, and
8、 Related MaterialsE178 Practice for Dealing With Outlying ObservationsE255 Practice for Sampling Copper and Copper Alloys forthe Determination of Chemical CompositionE415 Test Method for Analysis of Carbon and Low-AlloySteel by Spark Atomic Emission SpectrometryE716 Practices for Sampling and Sample
9、 Preparation ofAluminum and Aluminum Alloys for Determination ofChemical Composition by Spectrochemical AnalysisE826 Practice for Testing Homogeneity of a Metal Lot orBatch in Solid Form by Spark Atomic Emission Spec-trometryE877 Practice for Sampling and Sample Preparation of IronOres and Related M
10、aterials for Determination of Chemi-cal Composition and Physical PropertiesE1086 Test Method forAnalysis ofAustenitic Stainless Steelby Spark Atomic Emission SpectrometryE1329 Practice for Verification and Use of Control Charts inSpectrochemical AnalysisE1806 Practice for Sampling Steel and Iron for
11、 Determina-tion of Chemical CompositionE2857 Guide for Validating Analytical Methods2.2 ISO Standards:4ISO Guide 30 Terms and Definitions Used in Connectionwith Reference MaterialsISO Guide 30/Amd. 1 Revision of definitions for referencematerial and certified reference materialISO Guide 35 Reference
12、 materialsGeneral and statisticalprinciples for certificationISO Guide 98-3 Guide to the Expression of Uncertainty inMeasurement (GUM: 1995)ISO/IEC 17025 General requirements for the competence oftesting and calibration laboratories1This test method is under the jurisdiction of ASTM Committee E01 on
13、Analytical Chemistry for Metals, Ores, and Related Materials and is the directresponsibility of Subcommittee E01.22 on Laboratory Quality.Current edition approved Feb. 15, 2015. Published March 2015. DOI: 10.1520/E2972-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontac
14、t ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American National Standards Institute (
15、ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 DefinitionsFor definitions of terms used in this guide,refer to Terminology E135.3.2 Definitions
16、 of Terms Specific to This Standard:3.2.1 development report, ndocument giving detailed in-formation on the preparation of an in-house reference materialand the methods of measurement used in obtaining the as-signed values.3.2.2 in-house reference material, iRM, nreference mate-rial with documented
17、homogeneity that is intended for use forquality control purposes, calibration, evaluation of acalibration, or standardization whose values may have limitedtraceability and for which rigorously derived uncertainty infor-mation is not mandatory.3.2.3 method of demonstrated accuracy, ntest method forwh
18、ich proof of accuracy has been published even though itmay not fall within the category of a reference method.3.2.4 metrological traceability, nproperty of a measure-ment result or the value of a reference material whereby it canbe related, with a stated uncertainty, to stated referencesthrough an u
19、nbroken chain of comparisons.3.2.5 primary reference method, nanalytical procedurethat does not require the use of calibrants to achieve accurateresults, rather the result is based on a defined physical constantor a derived physical constant.3.2.5.1 DiscussionExamples include gravimetry,coulometry,
20、specific titrimetric methods, and isotope dilutionmass spectrometry. Each individual laboratory should validateits performance of such methods with reference materials.3.2.6 reference method, nthoroughly investigated method,clearly and exactly describing the necessary conditions andprocedures for th
21、e measurement of one or more property valuesthat has been shown to deliver accuracy and precision com-mensurate with its intended use and can therefore be used toassess the accuracy of other methods for the samemeasurement, particularly in permitting the characterization ofan RM (ISO Guide 30).3.2.6
22、.1 DiscussionThis includes all national or interna-tional standard methods, which may not be classified asprimary reference methods because they are calibrated againststandard solutions of pure chemical substances.3.2.7 uncertainty, ndefined by ISO Guide 98-3 as a“parameter associated with the resul
23、t of a measurement thatcharacterises the dispersion of the values that could reasonablybe attributed to the measurand.”4. Significance and Use4.1 This document provides guidance for the implementa-tion of procedures for the preparation, testing, and documen-tation of an in-house reference material (
24、hereafter called aniRM) to be used for a number of purposes, enumerated in thefollowing document, associated with development, validation,and control of chemical and physical measurement processes.4.2 This guide is primarily concerned with characterizationof the chemical compositions of metals, ores
25、, and relatedmaterials. For all these materials, there is a continuing, strongdemand for reference materials (RMs) that is difficult formetrology institutes and private certified reference material(CRM) developers to meet because CRM development re-quires substantial investments of time and money. T
26、he metalsand mining industries consume RMs and create new productand by-product compositions at high rates. They use analyticalmethods that provide rapid and accurate determinations, andboth quality assurance and quality control can be maintainedusing efficient procedures provided appropriate iRMs a
27、reavailable.4.3 The user of this guide must recognize that developmentof an iRM for any purpose carries with it the responsibility todesign and execute the development process correctly, and todocument the process thoroughly. In addition, the user of aniRM bears the responsibility for correct use of
28、 the iRMmaterial within its design limitations.4.4 This guide contains discussions on material selectionand sampling for RMs with some attention given to conversionto the final forms.4.5 The use of iRMs is appropriate for control chart proce-dures to demonstrate that chemical measurement processes a
29、reunder statistical control. This function requires demonstrationof sufficient homogeneity of a material, but it does not requireassignment of chemical and physical property values withassociated, exhaustively evaluated uncertainties.4.6 The use of iRMs is appropriate for calibration of testmethods
30、and evaluation of calibrations in several ways, includ-ing checking for bias, systematic testing of corrections formatrix effects, and testing of sample preparation procedures.See Section 6. This guide provides explanations of generalcases in which an iRM can be used as part of a validationprocess (
31、see Guide E2857).4.7 Because this document is a standard guide, it is intendedto educate those who are involved in laboratory operation,quality system development and maintenance, and accredita-tion of laboratory operations within the scope of a qualitysystem. However, this guide does not constitute
32、 requirementsfor assessment and accreditation.5. Hazards5.1 The preparation of metal RMs can involve hazardsassociated with melting, casting, heat treating, forging,atomizing, pickling, shot blasting, machining, and sampling.5.2 Hazards may be encountered in crushing, grinding, andsieving particulat
33、e and powdered materials such as ores andrelated metallurgical materials.5.3 For precautions related to the analysis of RMs, seePractices E50.6. Uses of iRMs and Information Requirements Relatedto the Applications6.1 Process Control:6.1.1 For efficient, high throughput in a laboratory, chemicalmeasu
34、rement processes, namely test methods, must be keptunder statistical control. Perhaps the most convenient way toaccomplish this control is to measure one or more materials atE2972 152appropriate time intervals. When the material(s) can be treatedas a regular sample and taken through all steps of the
35、 process,the measured results easily can be used to demonstrate statis-tical control of the entire chemical measurement process.6.1.2 A product-based material demonstrated to be suffi-ciently homogeneous can be prepared in sufficient quantity toenable its use for a long period of time. A sufficient
36、level ofhomogeneity is defined as providing repeatability variance lowenough to maintain a process control chart that ensures theuncertainty goals of the test method are met on a routine basis.6.1.3 The material chosen for this purpose should be dem-onstrated to be stable for at least the length of
37、time it will beused for control charts. For most metals and alloys, stability isknown to be measured in years, if not decades. Stability ofnatural matrix geological and mineral materials may be lesscertain and may require monitoring. However, RM producershave demonstrated that mineral and geological
38、 materials can beprocessed and packaged in ways that provide long-term stabil-ity measured in years.6.1.4 For process control, it is not necessary to developvalues traceable to the International System of Units (SI) orany CRMs. The laboratory simply runs the material as a routinesample at least 20 t
39、imes to establish a mean and repeatabilitystandard deviation. These measurements should be carried outover a time period chosen with consideration to other factorsaffecting routine use of the test method. Refer to PracticeE1329 for further guidance on the use of control charts.6.2 Drift CorrectionTh
40、e purpose of a drift correction iRMis to provide stable, high-precision signals for the constituentsof interest. In this case, it is not necessary to know the valuesof the amounts of the constituents. Homogeneity and stabilityshould be demonstrated as above, but the calculations can bedone in units
41、of the measured phenomenon on which theinstrumental or chemical technique is based. One example isthe count rate of fluorescent X-rays obtained under the chosenmeasurement conditions.6.2.1 To satisfy these requirements, it is necessary to have astable, homogeneous material that can be used numerous
42、timeswithout degradation and that gives a strong measured signal fora high correction point or a low signal for a low correctionpoint in the case of a two-point drift correction approach.6.3 Instrument ConditioningFor certain test methods, theequipment must be stabilized and conditioned for use on a
43、regular basis, typically daily. It is necessary to use materialssimilar in chemical and physical properties to the analysissamples, but it is not necessary to know accurately thecompositions of materials used for conditioning.6.3.1 It may be useful to have confidence that a conditioningmaterial is h
44、omogeneous and stable. However, the purpose isto show that the instrument is ready for calibration, and therequirements for homogeneity and stability can be relaxedrelative to the calibrants.6.4 Evaluation of Matrix Influence or SpectralInterferenceBoth of these phenomena involve systematiceffects o
45、f one constituent on another or on itself. To evaluatethe magnitude of an effect, a laboratory may require a set ofmaterials specially prepared to have known relationshipsamong the values of the subject constituents within the set.That is, the value of Constituent A in Material X may be twicethe val
46、ue in Material Y and three times the value of ConstituentA in Material Z. There may be multiple pairs of relatedconstituents in a set of materials. The known relationshipsallow the laboratory to calibrate influence and interferencecoefficients empirically or to validate coefficients determinedfrom f
47、irst principles.An iRM for evaluation of matrix influenceor spectral interference should have values obtained from anindependent test method or multiple methods of analysis.6.4.1 The materials in the set should be demonstrated to besufficiently homogeneous to be sampled at the appropriatequantity an
48、d maintain the required ratios of constituentamounts with sufficient precision for the uncertainty goals ofthe test method.6.4.2 Stability is a less stringent requirement because it istypical that the coefficient(s) need only be determined once,unless the instrumentation is modified significantly. T
49、his isconvenient because it is known that some artificial sets ofmaterials, even alloys, of this nature are unstable and may lastfor months instead of years.6.5 CalibrationAn iRM can be used as a calibrant inmuch the same way as a CRM. This is a key role because notall CRM producers can keep pace with the development of newalloys and the development or modification of manufacturingspecifications.6.5.1 An iRM used for calibration should have been devel-oped with attention to homogeneity as with other uses of iRMs.6.5.2 An iRM for calibration should have values obtainedf
