1、Designation: F2617 15Standard Test Method forIdentification and Quantification of Chromium, Bromine,Cadmium, Mercury, and Lead in Polymeric Material UsingEnergy Dispersive X-ray Spectrometry1This standard is issued under the fixed designation F2617; the number immediately following the designation i
2、ndicates 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 di
3、spersive X-rayfluorescence (EDXRF) spectrometric procedure for identifica-tion and quantification of chromium, bromine, cadmium,mercury, and lead in polymeric materials.1.2 This test method is not applicable to determine totalconcentrations of polybrominated biphenyls (PBB), polybro-minated diphenyl
4、 ethers (PBDE) or hexavalent chromium. Thistest method cannot be used to determine the valence states ofatoms or ions.1.3 This test method is applicable for a range from 20 mg/kgto approximately 1 wt % for chromium, bromine, cadmium,mercury, and lead in polymeric materials.1.4 This test method is ap
5、plicable for homogeneous poly-meric material.1.5 The values stated in SI units are to be regarded as thestandard. Values given in parentheses are for information only.1.6 This test method is not applicable to quantitative deter-minations for specimens with one or more surface coatingspresent on the
6、analyzed surface; however, qualitative informa-tion may be obtained. In addition, specimens less than infi-nitely thick for the measured X rays, must not be coated on thereverse side or mounted on a substrate.1.7 This standard does not purport to address all of thesafety concerns, if any, associated
7、 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 Standards:2D883 Terminology Relating to PlasticsD3641 Practice for Injecti
8、on Molding Test Specimens ofThermoplastic Molding and Extrusion MaterialsD4703 Practice for Compression Molding ThermoplasticMaterials into Test Specimens, Plaques, or SheetsD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement Sys
9、tem PerformanceE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducti
10、ng an Interlaboratory Study toDetermine the Precision of a Test MethodE1361 Guide for Correction of Interelement Effects inX-Ray Spectrometric AnalysisF2576 Terminology Relating to Declarable Substances inMaterials3. Terminology3.1 Definitions:3.1.1 Definitions of terms applying to XRF, plastics and
11、declarable substances appear in Terminology E135, Terminol-ogy D883 and Terminology F2576, respectively.3.1.2 Compton scatterthe inelastic scattering of an X-rayphoton through its interaction with the bound electrons of anatom; this process is also referred to as incoherent scatter.1This test method
12、 is under the jurisdiction of ASTM Committee F40 onDeclarable Substances in Materials and is the direct responsibility of SubcommitteeF40.01 on Test Methods.Current edition approved Aug. 1, 2015. Published October 2015. Originallyapproved in 2008. Last previous edition approved in 2008 as F2617-081.
13、 DOI:10.1520/F2617-15.2For 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.Copyright ASTM International, 100 Barr
14、Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.3 Rayleigh scatterthe elastic scattering of an X-rayphoton through its interaction with the bound electrons of anatom; this process is also referred to as coherent scatter.3.1.3.1 DiscussionThe measured count rate of Comp
15、tonand Rayleigh scattered radiation varies depending upon speci-men composition and may thus be used to compensate formatrix effects. One option is to use the measured count rate ofthe Compton scatter in the same manner as the measured countrate of an internal standard element. Alternatively, the me
16、a-sured count rate of the Compton scatter or the Compton/Rayleigh scatter ratio may be used indirectly for estimating theeffective mass absorption coefficient of the specimen, which isused to compensate for matrix effects. The concept of correc-tions based on the Compton scatter effect is discussed
17、as anoptional part of several calibration choices in this standard.3.1.4 fundamental parameters (FP) modela model forcalibration of X-ray fluorescence response, including the cor-rection of matrix effects, based on the theory describing thephysical processes of the interactions of X rays with matter
18、.3.1.5 homogeneous polymeric materialpolymeric mate-rial is considered homogeneous for XRF when the elementalcomposition is independent with respect to the measuredlocation on the specimen and among separate specimensprepared from the same polymeric material.3.1.6 infinite thickness (or critical thi
19、ckness) the thicknessof specimen which, if increased, yields no increase in intensityof secondary X rays, due to absorption by the polymer matrix.3.1.6.1 DiscussionThis thickness varies with secondaryX-ray energy, or wavelength.3.2 Abbreviations:3.2.1 EDXRFenergy dispersive X-ray fluorescence3.2.2 F
20、Pfundamental parameters3.2.3 PBBpolybrominated biphenyl3.2.4 PBDEpolybrominated diphenyl ether4. Summary of Test Method4.1 The optimum test sample is a smooth plaque or disklarge enough to cover the viewed area of the spectrometer.Suitable specimens may be die-cut from extruded sheets, ormolded from
21、 resin pellets, from powders or from granules.4.2 The specimen is placed in the X-ray beam, and theappropriate region of its spectrum is measured to give the countrates or fluorescent intensities of lead, mercury, cadmium,chromium and bromine.4.3 The EDXRF spectrometer is calibrated by one of severa
22、lapproaches including fundamental parameters and empirical,classical curve construction, with either empirical or theoreti-cal influence coefficients, from measured polymer referencematerials. The calibration may be performed by the manufac-turer or by the user.4.4 Choices of appropriate characteris
23、tic X-ray lines andspectrometer test conditions may vary according to eachelement and with factors such as detector response, concentra-tion range and other elements present in the polymer matrix.5. Significance and Use5.1 This test method is intended for the determination ofchromium, bromine, cadmi
24、um, mercury, and lead, in homoge-neous polymeric materials. The test method may be used toascertain the conformance of the product under test to manu-facturing specifications. Typical time for a measurement is 5 to10 min per specimen, depending on the specimen matrix andthe capabilities of the EDXRF
25、 spectrometer.6. Interferences6.1 Spectral InterferencesSpectral interferences resultfrom the behavior of the detector subsystem of the spectrom-eter and from scattering of X rays by the specimen, by asecondary target or by a monochromator, if the spectrometer isso equipped. Overlaps among the X-ray
26、 lines from elements inthe specimen are caused by the limited resolution of thedetection subsystem. Depending upon the resolution of thedetector system, the peaks from Zn, Br, Hg and Pb may overlapwith one another. Peaks from Cd may overlap with peaks fromCa, Sn, or other elements. Interactions of p
27、hotons and electronsinside the detector give rise to additional peaks in a spectrumknown as escape peaks and sum peaks. Fundamental Param-eters equations require that the measured net count rates be freefrom line overlap effects. Some empirical approaches incorpo-rate line overlap corrections in the
28、ir equations. Manufacturerssoftware may provide tools to compensate for overlappedpeaks, escape peaks, and sum peaks in spectra. The degree ofline overlap and the best method to account or correct for itmust be ascertained on an individual basis and must beconsidered when calibrating the instrument.
29、6.2 Interelement EffectsInterelement effects, also calledmatrix effects, 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
30、in turn emit a fluorescent X ray, increasing the apparentsensitivity for the second element. Mathematical methods maybe used to compensate for matrix effects. A number ofmathematical correction procedures are commonly utilizedincluding full FPtreatments and mathematical models based oninfluence coef
31、ficient algorithms. The influence coefficients maybe calculated either from first principles or from the empiricaldata, or some combination of the two approaches. See GuideE1361 for examples of these approaches. Also, consult thesoftware manual for the spectrometer for information on theapproaches p
32、rovided with the spectrometer. Any of these thatwill achieve the necessary analytical accuracy is acceptable.Examples of common interelement effects are listed in Table 1.7. Apparatus7.1 EDXRF SpectrometerDesigned for X-ray fluorescenceanalysis with energy dispersive selection of radiation. Thespect
33、rometer is equipped with specimen holders and a speci-men chamber. Any EDXRF spectrometer may be used if itsdesign incorporates the following features.7.1.1 Source of X-ray Excitation , capable of exciting therecommended lines listed in Table 2, typically an X-ray tube.F2617 1527.1.2 X-ray Detector,
34、 with sufficient energy resolution toresolve the recommended lines listed in Table 2. An energyresolution of better than 250 eV at Mn K-L2,3(K) has beenfound suitable.7.1.3 Signal Conditioning and Data Handling Electronicsthat include the functions of X-ray counting and peak process-ing.7.2 The foll
35、owing spectrometer features and accessories areoptional:7.2.1 Beam FiltersUsed to make the excitation moreselective and 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 fo
36、r 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 Vacuum PumpFor improved sensitivity of atomicnumbers 20 (Ca) or lower, the X-ray optical pa
37、th may beevacuated using a mechanical pump.7.2.5 Helium FlushFor improved sensitivity of atomicnumbers 20 (Ca) or lower, the X-ray optical path may beflushed with helium.7.3 Drift Correction Monitor(s)Due to instability of themeasurement system, the sensitivity and background of thespectrometer may
38、drift with time. Drift correction monitorsmay be used to correct for this drift. The optimum driftcorrection monitor specimens are permanent materials that arestable with time and repeated exposure to X rays Note 1.NOTE 1Suitable drift correction monitors may be fused bead speci-mens containing the
39、relevant elements (Cr, Br, Cd, Hg, and Pb) orelements that have fluorescence with the same energies as the elements ofinterest.8. Reagents and Materials8.1 Purity of Reagents3Reagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the
40、 specifications of the Committee onAnalytical Reagents of the American Chemical Society (ACS)where such specifications are available. Other grades may beused provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determi
41、nation. Reagents used include allmaterials used for the preparation of reference materials andfor cleaning of specimens.8.2 Reagents:8.2.1 Isopropanol or ethanol.8.2.2 Nitric acid (HNO3).8.2.3 Hexane.8.2.4 Deionized water (H2O).8.3 GlovesDisposable cotton gloves are recommended forhandling reference
42、 materials and other specimens to minimizecontamination.8.4 Appropriate personal protective equipment for the han-dling of reagents.8.5 Reference Materials:8.5.1 Polymer reference materials are available from bothmetrology institutes and commercial sources. Some are pro-vided in disk form, and some
43、are available as granules orextruded pellets.8.5.2 Reference materials may be prepared by addingknown amounts of pure compounds or additives (or both), toan appropriate polymeric base material. It is recommended tomake reference materials using the same base polymer as theunknown samples.8.5.2.1 Tho
44、rough mixing of ingredients is required foroptimum homogeneity. Options may include grinding, melt-blending, repeated extrusion, and solvent dissolution.8.5.2.2 Elemental concentrations may be calculated fromthe concentrations and molecular formulae of the compoundsand additives used.8.5.2.3 The ele
45、mental compositions of user-prepared refer-ence materials must be confirmed by one or more independentanalytical methods.8.6 Quality Control Samples:8.6.1 To ensure the quality of the results, analyze qualitycontrol (QC) samples at the beginning and at the end of eachbatch of specimens or after a fi
46、xed number of specimens, but at3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Annular Standards for LaboratoryChemicals, BDH Ltd. Poole, Dorset, UK, and
47、 the United States Pharmacopeia andNational Formulary, U.S. Pharmacopeia Convention, Inc. (USPC), Rockville, MD.TABLE 1 Common Interelement Effects in Formulated PlasticsCause EffectAbsorption by Cl in PVC Reduced sensitivity for all analytes ascompared to when they are occurringat the same concentr
48、ation level inpolyolefinsPolymers of similar composition butdifferences in the relativeconcentrations of H and CDifferences in C/H among calibrantsand samples may result in biases of afew percent (relative).Unmeasured elements B, N, O, and Fpresent in the matrix of the polymer,for example, amide, fl
49、uorinated, andterephthalate compounds.If concentrations differ from thecalibrants, substantial concentrationsof these elements may causesignificant changes in both apparentsensitivity and background count rates.Absorption by elements present inflame-retardant compounds such asPBBs, PBDEs, and Sb2O3Reduction of apparent sensitivity formost analytesAbsorption by Na, P, S, Ca, Ti, Zn,Mo, Sn, Ba, and other elementsincluded in a formulation as fillers orperformance additivesReduction of apparent sensitivity formost analytesTABLE 2 Recommended X-ray Lines for Ind
