1、Designation: F3078 15Standard Test Method forIdentification and Quantification of Lead in Paint and SimilarCoating Materials using Energy Dispersive X-rayFluorescence Spectrometry (EDXRF)1This standard is issued under the fixed designation F3078; the number immediately following the designation indi
2、cates 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 test method describes an energy dispe
3、rsive X-rayfluorescence (EDXRF) procedure for determining the arealmass of Pb in mass per unit area in paint and similar coatingson common substrates of toys and consumer products, such asplastic, wood, steel, aluminum, zinc alloys or fabric.1.2 This test method is applicable for homogeneous, single
4、layer paint or similar coatings. The method does not apply tometallic coatings.1.3 This test method is applicable for a range of Pb mass perunit area from 0.36 g/cm2to approximately 10 g/cm2for Pbin paint and similar coatings applied on common substrates.The lower limit of this test method is betwee
5、n 0.36 and 0.75g/cm2depending on the nature of the substrate. Based on theresults obtained during the interlaboratory study (ASTM Re-port F40-1004), it is estimated that the applicable range of thismethod can be extended up to 50 g/cm2.1.4 The values stated in SI units are to be regarded asstandard.
6、 Values given in parentheses are for information only.1.5 This standard does not 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
7、of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D16 Terminology for Paint, Related Coatings, Materials, andApplicationsD883 Terminology Relating to PlasticsD1005 Test Method for Measurement of Dry-Film Thick-ness of Organic Coatings Using MicrometersD6132 Test Metho
8、d for Nondestructive Measurement of DryFilm Thickness of Applied Organic Coatings Using anUltrasonic Coating Thickness GageD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD7091 Practice for Nondestructive Me
9、asurement of DryFilm Thickness of Nonmagnetic Coatings Applied toFerrous Metals and Nonmagnetic, Nonconductive Coat-ings Applied to Non-Ferrous MetalsE135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE177 Practice for Use of the Terms Precision and Bias inASTM T
10、est MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodC693 Test Method for Density of Glass by BuoyancyF2576 Terminology Relating to Declarable Substances inMaterials2.2 Other Standards:Consumer Products Safety Improvement Act of 2008 (CP-SIA), Pu
11、blic Law 110-314, August 14, 20083SSPC-PA2 Paint Application Standard No. 2, Measurementof Dry Coating Thickness with Magnetic Gauges4NIST Special Publication 829 Use of NIST Standard Refer-ence Materials for Decisions on Performance of Analyti-cal Chemical Methods and Laboratories53. Terminology3.1
12、 Definitions:3.1.1 Definitions of terms applying to X-ray fluorescence(XRF) spectrometry, plastics and declarable substances appear1This test method is under the jurisdiction of ASTM Committee F40 onDeclarable Substances in Materials and is the direct responsibility of SubcommitteeF40.01 on Test Met
13、hods.Current edition approved July 1, 2015. Published September 2015. DOI:10.1520/F3078-152For 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 Sum
14、mary page onthe ASTM website.3Full text is available on the Consumer Products Safety Commission website:http:/www.cpsc.gov/PageFiles/113865/cpsia.pdf.4Available from Society for Protective Coatings (SSPC), 40 24th St., 6th Floor,Pittsburgh, PA 15222, http:/www.sspc.org.5Available from National Insti
15、tute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1in Terminology E135, Terminology D883 and TerminologyF2576, respectivel
16、y. Definitions of terms applying to Paintappear in Terminology D16.3.1.2 areal mass (or mass per unit area), nmass ofsubstance (element) contained in a unit area of surface overwhich substance (element) is uniformly spread.3.1.2.1 DiscussionThis way of expressing the mass of asubstance is typical an
17、d useful when material is present in aform of thin layer rather than bulk volume. The term is used notonly in XRF analysis but also in a variety of coating industryapplications. Areal mass is related to mass fraction through thethickness and density of the layer (see X1 for an example).3.1.3 Compton
18、 scatter, nthe inelastic scattering of anX-ray photon through its interaction with the bound electronsof an atom; this process is also referred to as incoherent scatter.3.1.4 empirical method, na method for calibration ofX-ray fluorescence response of an analyzer using wellcharacterized, representat
19、ive samples (calibrants).3.1.5 fundamental parameters (FP) method, na methodfor calibration of X-ray fluorescence response of an analyzer,which includes the correction of matrix effects based on thetheory describing the physical processes of the interactions ofX rays with matter.3.1.6 homogeneous co
20、ating, nthe coatings such as paintsor similar types are considered homogeneous for purposes ofXRF analysis when their elemental composition is independentwith respect to the measured location on the specimen andamong separate specimens obtained from the same material.3.1.7 infinite thickness, nthe t
21、hickness of a specimenabove which no measurable count rate increase is observed forany analyte is referred to as infinite thickness.3.1.7.1 DiscussionBulk materials with a matrix of lowatomic number elements, such as polymers or wood, exhibitrelatively low X-ray absorption. This leads to a requireme
22、ntthat for the best quantitative analysis the specimens must bethick, generally in excess of several millimeters, depending onthe X-ray energies to be measured and the actual compositionof the matrix. In general, more accurate and precise results canbe obtained when the reference materials and the u
23、nknownsamples are of infinite thickness or if thicknesses of thereference materials and unknown samples are at least within10 % relative of each other. Typical substrates on which paintis applied may often be considered to be of infinite thicknessfor the purpose of XRF analysis.3.1.8 Rayleigh scatte
24、r, nthe elastic scattering of an X-rayphoton through its interaction with the bound electrons of anatom; this process is also referred to as coherent scatter.3.1.8.1 DiscussionThe measured count rate of Comptonand Rayleigh scattered radiation varies depending upon speci-men composition. The measured
25、 count rate of the Comptonand Rayleigh scattered radiation or the ratio of Compton/Rayleigh scatter may be used to compensate for matrix effectsspecific to XRF analysis.3.1.9 screening, nscreening is an analytical test procedureto determine the presence or absence of a substance (such asPb) or compo
26、und in the representative part or section of aproduct, relative to the value or values accepted as the criterionfor such decision.3.1.9.1 DiscussionThe value or values accepted as thecriterion for decision shall be within the applicable range andabove the limit of detection of the method. If the scr
27、eening testproduces values that are not conclusive, then additional analy-sis or other follow-up actions may be necessary to make a finalpresence/absence decision.3.1.10 thin sample, napplied paints and similar coatingsrepresent a type of sample which is markedly different from abulk sample of infin
28、ite thickness. The absorption and enhance-ment phenomena typical of XRF analysis of bulk materials areminimized by the fact that layer of paint is “thin”. A layer ofpaint is considered “thin” for XRF purposes if it fulfills thefollowing criterion6:m #0.1 (1)where: = a mass absorption coefficient of
29、the sample for excitingradiation and characteristic X radiation of excited ele-ment in cm2/g, andm = mass per unit area of the sample (areal mass) in g/cm2.3.2 Acronyms:3.2.1 EDXRFenergy dispersive X-ray fluorescence3.2.2 FPfundamental parameters4. Summary of Test Method4.1 An EDXRF analyzer that ha
30、s been calibrated usingeither a fundamental parameters approach or an empiricalapproach is used to directly measure the areal mass of Pb inpaint applied on any of the common substrates described in 1.1by placing the painted surface of the object to be tested over themeasuring aperture (window) of th
31、e analyzer and initiating themeasurement. Alternatively, when using a handheld XRFanalyzer, its measuring aperture (window) should be placedflush against the painted area of the object. The analyzer can becalibrated either by the manufacturer or by the user.4.2 The test sample for this method should
32、 be a single,homogenous layer of dry, solid paint or similar coating appliedover substrate material.4.3 The test sample should cover the measuring aperture ofan analyzer.NOTE 1Increased quantitative error may result if the coated samplearea does not cover the measuring aperture of the analyzer. Corr
33、ectionschemes may be available to adjust the measurements of such samples.These schemes have not been evaluated for this method. Refer to theanalyzers manufacturers instructions for guidance.4.4 The test sample is irradiated by an X-ray source, and theresulting characteristic X rays of Pb and other
34、elements present6Rhodes J.R., Stout J.A., Schindler S.S. and Piorek S., “Portable X-ray SurveyMeters for In-Situ Trace Element Monitoring ofAir Particulates,” in Toxic Materialsin The Atmosphere: Sampling and Analysis, ASTM STP 786, ASTM International,1981, pp. 7082.F3078 152in the sample are measur
35、ed. A value of the Pb mass per unitarea of the paint sample is calculated and compared to thespecification limit against which the sample is being evaluated.5. Significance and Use5.1 This test method provides for analysis of Pb in appliedpaint using measurement times on the order of several minutes
36、.It can be used to determine whether the sample of applied painthas an areal mass of Pb either substantially less than aspecification limit, and therefore does not exceed it, or sub-stantially above the specified limit, and therefore exceeds it.5.2 If the value obtained with this test method falls c
37、lose toa specification limit, a more precise test method may berequired to positively determine whether Pb content does ordoes not exceed the specified limit.6. Interferences6.1 Spectral InterferencesSpectral interferences in XRFanalysis manifest themselves as overlaps of spectral peaksrepresenting
38、lines of different X-ray energies. These overlapsare the result of limited energy resolution of detectors. Forexample, the As K peak overlaps completely the Pb L peak.Interactions of photons with the detector and limitations ofassociated electronics give rise to additional peaks in aspectrum known a
39、s escape peaks and sum peaks. For example,high content of iron in a paint or substrate may produce a sumpeak that will overlap with the Pb L line. FundamentalParameters equations require that the measured net count ratesbe free from line overlap effects. Some empirical approachesincorporate line ove
40、rlap corrections in their equations. Thesoftware used for spectrum treatment must compensate for lineoverlaps. Manufacturers software typically provides tools tocompensate for peak overlaps, escape peaks and sum peaks inspectra.6.2 Matrix InterferencesInterelement effects, also calledmatrix effects,
41、 exist among all elements as the result ofabsorption of fluorescent X rays (secondary X rays) by atomsin the specimen. Absorption reduces the apparent sensitivityfor the element. In contrast, the atom that absorbs the X raysmay in turn emit a fluorescent X ray, increasing the apparentsensitivity for
42、 the element it represents. Mathematical methodsmay be used to compensate for matrix effects. A number ofmathematical correction procedures are commonly utilizedincluding full FPtreatments and mathematical models based oninfluence coefficient algorithms.6.3 Substrate InterferencesElements in the sub
43、strate mayinterfere with determination of Pb in a layer of paint. Forexample, if both substrate and paint contain Pb, the compositePb signal will include contributions from both sources andeffectively may result in a significant positive bias of Pb massper unit area. For example, a plastic substrate
44、 containing 100mg/kg of Pb may produce apparent areal Pb concentration of30 g/cm2, even if paint on such substrate does not contain Pb.7. Apparatus7.1 EDXRF Spectrometer, designed for X-ray fluorescenceanalysis of materials with energy dispersive selection ofradiation. Any EDXRF spectrometer can be
45、used if its designincorporates the following features.7.1.1 A means of repeatable sample presentation foranalysisFor hand-held spectrometers this is usually a small,flat plane with round, oval or rectangular aperture that comesinto direct contact with the sample and through which X rayscan reach the
46、 sample under test. Laboratory embodiments ofanalyzer design may have specimen holders and a specimenchamber.7.1.2 Source of X-ray Excitation, typically an X-ray tube,capable of exciting the Pb L2-M4(L1) line (secondary line: PbL3-M4,5(L1,2).7.1.3 X-ray Detector, with energy resolution sufficient to
47、resolve the recommended Pb L2-M4(L1) line from X-raylines of other elements present in sample. An energy resolutionof better than 250 eV at the energy of Mn K-L2,3(K) has beenfound suitable for the purpose of Pb analysis.7.1.4 Signal conditioning and data handling electronics,that include the functi
48、ons of X-ray counting and peak/spectrumprocessing.7.1.5 Data Processing Software, for calculating elementalcomposition of sample from measured X-ray intensities usingone of calibration methods.7.2 The following spectrometer features and accessories areoptional.7.2.1 Beam FiltersUsed to make the exci
49、tation moreselective and to reduce background count rates.7.2.2 Secondary TargetsUsed to produce semi-monochromatic radiation enhancing sensitivity for selectedX-ray lines and to reduce spectral background for improveddetection limits. The use of monochromatic radiation alsoallows the simplification of FP calculations.7.2.3 Specimen SpinnerUsed to reduce the effect of sur-face irregularities of the specimen.7.2.4 Built-in CameraUsed to capture and record animage of the tested area/object.7.3 Drift Correction MonitorsDue to potential in
