ASTM F2617-08
(Test Method)Standard Test Method for Identification and Quantification of Chromium, Bromine, Cadmium, Mercury, and Lead in Polymeric Material Using Energy Dispersive X-ray Spectrometry
Standard Test Method for Identification and Quantification of Chromium, Bromine, Cadmium, Mercury, and Lead in Polymeric Material Using Energy Dispersive X-ray Spectrometry
SIGNIFICANCE AND USE
This test method is intended for the determination of chromium, bromine, cadmium, mercury, and lead, in homogeneous polymeric materials. The test method may be used to ascertain the conformance of the product under test to manufacturing specifications. Typical time for a measurement is 5 to 10 min per specimen, depending on the specimen matrix and the capabilities of the EDXRF spectrometer.
SCOPE
1.1 This test method describes an energy dispersive X-ray fluorescence (EDXRF) spectrometric procedure for identification and quantification of chromium, bromine, cadmium, mercury, and lead in polymeric materials.
1.2 This test method is not applicable to determine total concentrations of polybrominated biphenyls (PBB), polybrominated diphenyl ethers (PBDE) or hexavalent chromium. This test method cannot be used to determine the valence states of atoms or ions.
1.3 This test method is applicable for a range from 20 mg/kg to approximately 1 wt % for chromium, bromine, cadmium, mercury, and lead in polymeric materials.
1.4 This test method is applicable for homogeneous polymeric material.
1.5 The values stated in SI units are to be regarded as the standard. Values given in parentheses are for information only.
1.6 This test method is not applicable to quantitative determinations for specimens with one or more surface coatings present on the analyzed surface; however, qualitative information may be obtained. In addition, specimens less than infinitely thick for the measured X rays, must not be coated on the reverse side or mounted on a substrate.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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Designation: F 2617 – 08
Standard Test Method for
Identification and Quantification of Chromium, Bromine,
Cadmium, Mercury, and Lead in Polymeric Material Using
Energy Dispersive X-ray Spectrometry
This standard is issued under the fixed designation F 2617; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D 3641 Practice for Injection Molding Test Specimens of
Thermoplastic Molding and Extrusion Materials
1.1 This test method describes an energy dispersive X-ray
D 4703 Practice for Compression Molding Thermoplastic
fluorescence (EDXRF) spectrometric procedure for identifica-
Materials into Test Specimens, Plaques, or Sheets
tion and quantification of chromium, bromine, cadmium,
D 6299 Practice for Applying Statistical Quality Assurance
mercury, and lead in polymeric materials.
and Control Charting Techniques to Evaluate Analytical
1.2 This test method is not applicable to determine total
Measurement System Performance
concentrations of polybrominated biphenyls (PBB), polybro-
E29 Practice for Using Significant Digits in Test Data to
minateddiphenylethers(PBDE)orhexavalentchromium.This
Determine Conformance with Specifications
test method cannot be used to determine the valence states of
E 135 Terminology Relating to Analytical Chemistry for
atoms or ions.
Metals, Ores, and Related Materials
1.3 Thistestmethodisapplicableforarangefrom20mg/kg
E 1361 Guide for Correction of Interelement Effects in
to approximately 1 wt % for chromium, bromine, cadmium,
X-Ray Spectrometric Analysis
mercury, and lead in polymeric materials.
F 2576 Terminology Relating to Declarable Substances in
1.4 This test method is applicable for homogeneous poly-
Materials
meric material.
1.5 The values stated in SI units are to be regarded as the
3. Terminology
standard. Values given in parentheses are for information only.
3.1 Definitions—DefinitionsoftermsapplyingtoXRF,plas-
1.6 This test method is not applicable to quantitative deter-
tics and declarable substances appear in Terminology E 135,
minations for specimens with one or more surface coatings
Terminology D 883 and Terminology F 2576, respectively.
present on the analyzed surface; however, qualitative informa-
3.1.1 Compton scatter—the inelastic scattering of an X-ray
tion may be obtained. In addition, specimens less than infi-
photon through its interaction with the bound electrons of an
nitely thick for the measured X rays, must not be coated on the
atom; this process is also referred to as incoherent scatter.
reverse side or mounted on a substrate.
3.1.2 Rayleigh scatter—the elastic scattering of an X-ray
1.7 This standard does not purport to address all of the
photon through its interaction with the bound electrons of an
safety concerns, if any, associated with its use. It is the
atom; this process is also referred to as coherent scatter.
responsibility of the user of this standard to establish appro-
3.1.2.1 Discussion—The measured count rate of Compton
priate safety and health practices and determine the applica-
and Rayleigh scattered radiation varies depending upon speci-
bility of regulatory limitations prior to use.
men composition and may thus be used to compensate for
2. Referenced Documents matrix effects. One option is to use the measured count rate of
the Compton scatter in the same manner as the measured count
2.1 ASTM Standards:
rate of an internal standard element. Alternatively, the mea-
D 883 Terminology Relating to Plastics
sured count rate of the Compton scatter or the Compton/
Rayleigh scatter ratio may be used indirectly for estimating the
This test method is under the jurisdiction of ASTM Committee F40 on
effective mass absorption coefficient of the specimen, which is
Declarable Substances in Materials and is the direct responsibility of Subcommittee
used to compensate for matrix effects. The concept of correc-
F40.01 on Test Methods.
Current edition approved Aug. 15, 2008. Published September 2008. tions based on the Compton scatter effect is discussed as an
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
optional part of several calibration choices in this standard.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F2617–08
3.1.3 fundamental parameters (FP) model—a model for with one another. Peaks from Cd may overlap with peaks from
calibration of X-ray fluorescence response, including the cor- Ca,Sn,orotherelements.Interactionsofphotonsandelectrons
rection of matrix effects, based on the theory describing the inside the detector give rise to additional peaks in a spectrum
physical processes of the interactions of X rays with matter. known as escape peaks and sum peaks. Fundamental Param-
3.1.4 homogeneous polymeric material—polymeric mate- etersequationsrequirethatthemeasurednetcountratesbefree
rial is considered homogeneous for XRF when the elemental from line overlap effects. Some empirical approaches incorpo-
composition is independent with respect to the measured rate line overlap corrections in their equations. Manufacturers’
location on the specimen and among separate specimens software may provide tools to compensate for overlapped
prepared from the same polymeric material. peaks, escape peaks, and sum peaks in spectra. The degree of
3.1.5 infinite thickness (or critical thickness)—the thickness line overlap and the best method to account or correct for it
of specimen which, if increased, yields no increase in intensity must be ascertained on an individual basis and must be
of secondary X rays, due to absorption by the polymer matrix. considered when calibrating the instrument.
3.1.5.1 Discussion—This thickness varies with secondary 6.2 Interelement Effects—Interelement effects, also called
X-ray energy, or wavelength. matrix effects, exist among all elements as the result of
3.2 Abbreviations: absorption of fluorescent X rays (secondary X rays) by atoms
3.2.1 EDXRF—energy dispersive X-ray fluorescence in the specimen. Absorption reduces the apparent sensitivity
3.2.2 FP—fundamental parameters for the element. In contrast, the atom that absorbs the X rays
3.2.3 PBB—polybrominated biphenyl may in turn emit a fluorescent X ray, increasing the apparent
3.2.4 PBDE—polybrominated diphenyl ether sensitivity for the second element. Mathematical methods may
be used to compensate for matrix effects. A number of
4. Summary of Test Method mathematical correction procedures are commonly utilized
includingfullFPtreatmentsandmathematicalmodelsbasedon
4.1 The optimum test sample is a smooth plaque or disk
influencecoefficientalgorithms.Theinfluencecoefficientsmay
large enough to cover the viewed area of the spectrometer.
be calculated either from first principles or from the empirical
Suitable specimens may be die-cut from extruded sheets, or
data, or some combination of the two approaches. See Guide
molded from resin pellets, from powders or from granules.
E 1361 for examples of these approaches. Also, consult the
4.2 The specimen is placed in the X-ray beam, and the
software manual for the spectrometer for information on the
appropriateregionofitsspectrumismeasuredtogivethecount
approaches provided with the spectrometer. Any of these that
rates or fluorescent intensities of lead, mercury, cadmium,
will achieve the necessary analytical accuracy is acceptable.
chromium and bromine.
Examples of common interelement effects are listed inTable 1.
4.3 TheEDXRFspectrometeriscalibratedbyoneofseveral
approaches including fundamental parameters and empirical,
7. Apparatus
classical curve construction, with either empirical or theoreti-
7.1 EDXRF Spectrometer—Designed for X-ray fluores-
cal influence coefficients, from measured polymer reference
cence analysis with energy dispersive selection of radiation.
materials. The calibration may be performed by the manufac-
The spectrometer is equipped with specimen holders and a
turer or by the user.
specimen chamber. Any EDXRF spectrometer may be used if
4.4 Choices of appropriate characteristic X-ray lines and
its design incorporates the following features.
spectrometer test conditions may vary according to each
element and with factors such as detector response, concentra-
tion range and other elements present in the polymer matrix.
TABLE 1 Common Interelement Effects in Formulated Plastics
Cause Effect
5. Significance and Use
Absorption by Cl in PVC Reduced sensitivity for all analytes as
5.1 This test method is intended for the determination of compared to when they are occurring
at the same concentration level in
chromium, bromine, cadmium, mercury, and lead, in homoge-
polyolefins
neous polymeric materials. The test method may be used to
Polymers of similar composition but Differences in C/H among calibrants
ascertain the conformance of the product under test to manu-
differences in the relative and samples may result in biases of a
facturing specifications.Typical time for a measurement is 5 to
concentrations of H and C few percent (relative).
10 min per specimen, depending on the specimen matrix and
Unmeasured elements B, N, O, and F If concentrations differ from the
the capabilities of the EDXRF spectrometer.
present in the matrix of the polymer, calibrants, substantial concentrations
for example, amide, fluorinated, and of these elements may cause
6. Interferences
terephthalate compounds. significant changes in both apparent
sensitivity and background count rates.
6.1 Spectral Interferences—Spectral interferences result
from the behavior of the detector subsystem of the spectrom-
Absorption by elements present in Reduction of apparent sensitivity for
flame-retardant compounds such as most analytes
eter and from scattering of X rays by the specimen, by a
PBBs, PBDEs, and Sb O
2 3
secondary target or by a monochromator, if the spectrometer is
so equipped. Overlaps among the X-ray lines from elements in Absorption by Na, P, S, Ca, Ti, Zn, Reduction of apparent sensitivity for
Mo, Sn, Ba, and other elements most analytes
the specimen are caused by the limited resolution of the
included in a formulation as fillers or
detection subsystem. Depending upon the resolution of the
performance additives
detectorsystem,thepeaksfromZn,Br,HgandPbmayoverlap
F2617–08
TABLE 2 Recommended X-ray Lines for Individual Analytes
used provided it is first ascertained that the reagent is of
sufficiently high purity to permit its use without lessening the
NOTE—Other choices may provide adequate performance.
accuracy of the determination. Reagents used include all
Analyte Preferred Line Secondary Line
materials used for the preparation of reference materials and
Chromium, Cr K-L (Ka )
2,3 1,2
for cleaning of specimens.
Bromine, Br K-L (Ka)K-M (Kb )
2,3 1,2 2,3 1,3
Cadmium, Cd K-L (Ka)K-M (Kb )
2,3 1,2 2,3 1,3 8.2 Reagents:
Mercury, Hg L -M (La )
3 4,5 1,2
8.2.1 Isopropanol or ethanol.
Lead, Pb L -M (Lb)L -M (La )
2 4 1 3 4,5 1,2
8.2.2 Nitric acid (HNO ).
8.2.3 Hexane.
8.2.4 Deionized water (H O).
7.1.1 Source of X-ray Excitation, capable of exciting the
recommended lines listed in Table 2, typically an X-ray tube. 8.3 Gloves—Disposablecottonglovesarerecommendedfor
7.1.2 X-ray Detector, with sufficient energy resolution to
handling reference materials and other specimens to minimize
resolve the recommended lines listed in Table 2. An energy contamination.
resolution of better than 250 eV at Mn K-L (Ka) has been
2,3 8.4 Appropriate personal protective equipment for the han-
found suitable.
dling of reagents.
7.1.3 Signal Conditioning and Data Handling Electronics
8.5 Reference Materials:
that include the functions of X-ray counting and peak process-
8.5.1 Polymer reference materials are available from both
ing.
metrology institutes and commercial sources. Some are pro-
7.2 The following spectrometer features and accessories are
vided in disk form, and some are available as granules or
optional:
extruded pellets.
7.2.1 Beam Filters—Used to make the excitation more
8.5.2 Reference materials may be prepared by adding
selective and reduce background count rates.
known amounts of pure compounds or additives (or both), to
7.2.2 Secondary Targets—Used to produce semi-
an appropriate polymeric base material. It is recommended to
monochromatic radiation enhancing sensitivity for selected
make reference materials using the same base polymer as the
X-ray lines and to reduce spectral background for improved
unknown samples.
detection limits. The use of monochromatic radiation also
8.5.2.1 Thorough mixing of ingredients is required for
allows the simplification of FP calculations.
optimum homogeneity. Options may include grinding, melt-
7.2.3 Specimen Spinner—Used to reduce the effect of sur-
blending, repeated extrusion, and solvent dissolution.
face irregularities of the specimen.
8.5.2.2 Elemental concentrations may be calculated from
7.2.4 Vacuum Pump—For improved sensitivity of atomic
the concentrations and molecular formulae of the compounds
numbers 20 (Ca) or lower, the X-ray optical path may be
and additives used.
evacuated using a mechanical pump.
7.2.5 Helium Flush—For improved sensitivity of atomic
8.5.2.3 The elemental compositions of user-prepared refer-
numbers 20 (Ca) or lower, the X-ray optical path may be
ence materials must be confirmed by one or more independent
flushed with helium.
analytical methods.
7.3 Drift Correction Monitor(s)—Due to instability of the
8.6 Quality Control Samples:
measurement system, the sensitivity and background of the
8.6.1 To ensure the quality of the results, analyze quality
spectrometer may drift with time. Drift correction monitors
control (QC) samples at the beginning and at the end of each
may be used to correct for this drift. The optimum drift
batchofspecimensorafterafixednumberofspecimens,butat
correction monitor specimens are permanent materials that are
least once each day of operation. If possible, the QC sample
stable with time and repeated exposure to X rays [Note 1].
shall be representative of samples typically analyzed. The
NOTE 1—Suitable drift correction monitors may be fused bead speci- materialshallbehomogeneousandstableundertheanticipated
mens containing the relevant elements (Cr, Br, Cd, Hg, and Pb) or
storage conditions. An ample supply of QC sample material
elements that have fluorescence with the same energies as the eleme
...
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