ASTM E1621-94(1999)
(Guide)Standard Guide for X-Ray Emission Spectrometric Analysis
Standard Guide for X-Ray Emission Spectrometric Analysis
SCOPE
1.1 This guide covers guidelines for developing and describing analytical procedures using a wavelength-dispersive X-ray spectrometer.
1.2 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.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E1621–94 (Reapproved 1999)
Standard Guide for
X-Ray Emission Spectrometric Analysis
This standard is issued under the fixed designation E1621; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope rays produced in the specimen are dispersed according to their
wavelengthbymeansofcrystalsorsyntheticmultilayers.Their
1.1 This guide covers guidelines for developing and de-
intensities are measured by suitable detectors at selected
scribing analytical procedures using a wavelength-dispersive
wavelengths and converted to counts by the detector. X-ray
X-ray spectrometer.
measurements are made based on the time required to reach a
1.2 This standard does not purport to address all of the
fixed number of counts, or on the total counts obtained for a
safety concerns, if any, associated with its use. It is the
fixedtime.Concentrationsoftheelementsaredeterminedfrom
responsibility of the user of this standard to establish appro-
the measured intensities of analyte X-ray lines using analytical
priate safety and health practices and determine the applica-
curves prepared with suitable reference materials. Either a
bility of regulatory limitations prior to use.
fixedmulti-channelsimultaneoussystemorasequentialmono-
2. Referenced Documents
chromatorsystemmaybeusedtoprovidedeterminationsofthe
elements.
2.1 ASTM Standards:
E135 Terminology Relating to Analytical Chemistry for
5. Significance and Use
Metals, Ores, and Related Materials
5.1 X-ray fluorescence spectrometry can provide an accu-
E305 Practice for Establishing and Controlling Spectro-
rate and precise determination of metallic and many non-
chemical Analytical Curves
metallic elements. This guide covers the information which
E1060 Practice for Interlaboratory Testing of Spectro-
shouldbeincludedinanX-rayspectrometricanalyticalmethod
chemical Methods of Analysis
and provides direction to the analyst for determining the
E1257 Guide for Evaluating Grinding Materials Used for
optimum conditions needed to achieve acceptable accuracy.
Surface Preparation in Spectrochemical Analysis
5.2 The accuracy of an analysis is a function of the
E1329 Practice for Verification and the Use of Control
3 calibration scheme, the sample preparation, and the sample
Charts in Spectrochemical Analysis
homogeneity. Close attention to all aspects of these areas is
E1361 Guide for Correction of Interelement Effects in
3 necessary to achieve the best results.
X-ray Spectrometric Analysis
E1622 Practice for Correction of Spectral Line Overlap in
6. Interferences
Wavelength-Dispersive X-Ray Spectrometry
6.1 Lineoverlaps,eithertotalorpartial,mayoccurforsome
3. Terminology elements.Fundamentalparameterequationsrequirethatthenet
intensities be free from line overlap effects. Some empirical
3.1 Definitions—For definitions of terms used in this guide,
schemesincorporatelineoverlapcorrectionsintheirequations.
refer to Terminologies E135 and E1361, Section.
See Guide E1622 for correction of line overlap effects.
4. Summary of Guide
6.2 Interelementeffectsormatrixeffectsmayexistforsome
elements.An empirical way to compensate for these effects is
4.1 Thetestspecimenispreparedwithaclean,uniform,flat
to prepare a series of calibration curves which cover the
surface. It may be prepared by grinding, polishing, or lathing a
designatedconcentrationrangestobeanalyzed.Alargesuiteof
metalsurfaceorbyfusingorbriquettingapowder.Thissurface
carefully designed reference materials is necessary for this
is irradiated with a primary source of X rays.The secondary X
procedure. A series of samples in which all elements are
relativelyconstant,exceptfortheanalyte,isnecessaryforeach
This guide is under the jurisdiction of ASTM Committee E-1 on Analytical
analyte which can be affected by other elements in the matrix.
ChemistryforMetals,Ores,andRelatedMaterialsandisthedirectresponsibilityof
In addition, several series for the same analyte may be
Subcommittee E01.20 on Fundamental Practices.
necessary, if the analyte is subject to large effects from some
Current edition approved July 15, 1994. Published September 1994.
other element in the matrix. The composition of the specimen
Annual Book of ASTM Standards, Vol 03.05.
Annual Book of ASTM Standards, Vol 03.06.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E1621
being analyzed must match closely the composition of the 7.2.4 Briquetting Press, providing pressures of up to 550
reference materials used to prepare the particular calibration MPa (80000 psi). The press shall be equipped with a mold
curves. assembly that provides a briquette that is compatible with the
6.2.1 Alternatively, mathematical methods may be used to X-ray specimen holder.
compensate for interelement or matrix effects. Various math-
7.2.5 FusionEquipment,withatimer,capableofheatingthe
ematical correction procedures are commonly utilized. See
sampleandfluxtoatleast1000°Candhomogenizingthemelt.
Guide E1361. Any of these that will achieve the necessary
7.2.6 FusionCrucibles,compatiblewiththefluxandsample
analytical accuracy is acceptable.
type:
7.2.6.1 Vitreous Carbon, 20 to 30-mL capacity, with flat
NOTE 1—Interelement effects are not interferences in the spectrometric
sense, but will contribute to errors in the analysis if not properly bottom 30 to 35 mm in diameter.
addressed. Caution must be used with mathematical models used in
7.2.6.2 95 % Platinum/5 % Gold Alloy, with 30 to 35-mL
computers to be sure that sufficient data is provided to adequately
capacity.
compensate for these effects. Reference materials which were not used in
7.2.7 Platinum/Gold Casting Mold (95 %/5 %),30to35-
the calibration should be analyzed as unknowns to verify the calibration.
mL capacity, with flat bottom 30 to 40 mm in diameter.
6.3 Additionally, interferences may occur from Compton
7.2.8 Polishing Wheel, suitable for polishing the fused
lines or characteristic lines generated by the target material of
button to obtain a flat uniform surface for irradiation.
the X-ray tube.These may be reduced or eliminated by the use
7.3 Excitation Source:
ofprimarybeamfilters,butthiswillcausesomelossofanalyte
7.3.1 X-Ray Tube Power Supply, providing a stable voltage
line intensity.
of sufficient energy to produce secondary radiation from the
6.4 Errors From Metallurgical Structure—Becausetheana-
specimen for the elements specified.
lyte intensity is affected by the mass absorption coefficient of
7.3.1.1 The instrument may be equipped with an external
the sample and mathematical models assume a homogeneous
line voltage regulator or a transient voltage suppressor.
sample,anerrormayresultiftheanalyteexistsinaninclusion.
For example, in a steel which contains carbon and carbide
7.3.2 X-Ray Tubes, with targets of various high-purity
formers such as titanium and niobium, the titanium may exist elements,thatarecapableofcontinuousoperationatpotentials
in a titanium-niobium carbide which has a lower mass absorp-
and currents that will excite the elements to be determined.
tion coefficient than iron for the titanium K-a line. The
7.4 Spectrometer,designedforX-rayemissionanalysis,and
intensity for titanium is higher in this sample than it would be
equipped with specimen holders and a specimen chamber.The
if the titanium were in solid solution.
chamber may contain a specimen spinner, and must be
equipped for vacuum or helium-flushed operation for the
7. Apparatus
determination of elements of atomic number 20 (calcium) or
7.1 Specimen Preparation Equipment for Metals:
lower.
7.1.1 Surface Grinder or Sander With Abrasive Belts or
7.4.1 Analyzing Crystals, flat or curved crystals with opti-
Disks, or Lathe,capableofprovidingaflat,uniformsurfaceon
mized capability for the diffraction of the wavelengths of
both the reference materials and test specimens.
interest. This may also include synthetic multi-layers for low
7.1.1.1 Abrasive disks are preferred over belts because the
atomic number elements.
platen on a belt sander tends to wear and produce a non-flat
7.4.2 Collimator, for limiting the characteristic X rays to a
surface on the specimen. If belt sanders are used, care must be
parallel bundle when flat crystals are used in the instrument.
exercised to be sure the platen is flat.
For curved crystal optics, a collimator is not necessary, but is
7.1.1.2 The grinding material should be selected so that no
replaced by entrance and exit slits.
significant contamination occurs for the elements of interest
7.4.3 Masks, for restricting the incident beam pattern on the
during the sample preparation. (Refer to Guide E1257.)
specimen.
7.1.1.3 Grinding belts or disks shall be changed at regular,
7.4.4 Detectors—sealed or gas-flow proportional counters
specified intervals in order that changes in abrasive grit due to
and scintillation counters are most commonly used.
repeated use does not affect the repeatability of the roughness
7.4.5 Vacuum System, for the determination of elements
of the sample finish. This is particularly important in alloys
whose radiation is absorbed by air.The system shall consist of
which exhibit smearing of a softer component over the sample
a vacuum pump, gage, and electrical controls to provide
matrix.
automatic pumpdown of the optical path, and maintain a
7.2 Specimen Preparation Equipment for Powders:
controlled pressure, usually 13 Pa (100 µm Hg) or less,
7.2.1 Jaw Crusher or Steel Mortar and Pestle, for initial
controlled to 63Pa(6 20 µm Hg).
crushing of lumps.
7.2.2 Plate Grinder or Pulverizer, with one static and one 7.5 Measuring System, consisting of electronic circuits ca-
rotating disk for further grinding. pable of amplifying and shaping pulses received from the
7.2.3 Rotary Disk Mill or Shatterbox, with hardened grind- detectors. The system shall be equipped with an appropriate
ing containers and timer control for final grinding. data output device.
E1621
7.5.1 Pulse Height Selectors, used to reduce pulses from Office, or similar handbooks on radiation safety, as well as
higher order X-ray lines and background. specific state regulations.
10.2 Monitoring Devices,eitherfilmbadgesordosimeters
8. Reagents and Materials
may be worn by all operating and maintenance personnel.
Safety practices shall conform to applicable local, state, and
8.1 Purity of Reagents—All reagents used in this test
federal regulations. To meet local, state, and federal radiation
methodshallconformtothe“ReagentGrade”specificationsof
standards,periodicradiationsurveysoftheequipmentforleaks
theAmericanChemicalSociety .Otherchemicalsmaybeused
and excessive scattered radiation shall be made by a qualified
provided it is first ascertained that they are of sufficient purity
person using an ionization-chamber detector. The personal
to permit their use without adversely affecting the expected
film badge survey record, the radiation survey record, and an
performance of the analysis.
equipmentmaintenancerecordshallbeavailableuponrequest.
8.2 Binders—Sodium tetraborate (Na B O ), polyethylene
2 4 7
10.3 Special precautions for operators and maintenance
glycol, fibrous cellulose, or spectrographic grade graphite
personnel shall be posted at the equipment site.
(−200 mesh, briquetting type).
10.4 Radiation Caution Signs shall be posted near the
8.3 Detector Gas (P-10), consisting of a mixture of 90%
X-ray equipment and at all entrances to the radiation area.
argon and 10% methane, for use with gas-flow proportional
10.5 Fail-Safe “X-Ray On” Warning Lights shall be used
counters.
on the equipment.
8.4 Fluxes—Sodium tetraborate (Na B O ), fused and
2 4 7
10.6 Routine checks of safety interlocks shall be docu-
dried;lithiumtetraborate(Li B O ),orlithiumtetraborateand
2 4 7
mented.
boric anhydrite (B O ) mixture (4 g+6 g).
2 3
11. Preparation of Reference Materials and Test
9. Reference Materials
Specimens
9.1 Certified Reference Materials are available from the
11.1 Throughout the procedure, treat reference materials
National Institute of Standards and Technology and other
and test specimens exactly the same way. Consistency in
certification agencies.
preparationofreferencematerialsandspecimensisessentialto
9.2 Reference Materials with compositions similar to that
ensure reproducible results.After the preparation procedure is
of the test specimen and containing varying amounts of the
established, it must be followed exactly. Variations in tech-
elements to be determined may be used provided they have
nique, such as grinding time, abrasive grit size or material,
been previously analyzed in accordance with ASTM test
particle size, binder material, sample-binder ratio, briquetting
methods.Thesereferencematerialsshallbehomogeneous,and
pressure, or holding times, can cause unreliable results.
free of voids or porosity.
11.2 Metal Samples—Prepare the reference materials and
9.3 The reference materials should cover the concentration
test specimens to provide a clean, flat uniform surface to be
ranges of the elements being determined. An appropriate
exposed to the X-ray beam. For abrasive sanding, select a grit
number of reference materials shall be used for each element,
size and use it exclusively for all reference materials and test
depending on the mathematical models being used.
specimens. See 7.1.1.2 and 7.1.1.3. Refinish the surface of the
reference materials and test specimens as needed to eliminate
10. Hazards
oxidation before measurement.
10.1 Occupational Health and Safety Standards for ionizing
6 11.3 Nonmetallic Samples—Dry the material. Then reduce
radiation shallbeobservedatallX-rayemissionspectrometer
it both in particle size and quantity, by crushing and pulveriz-
installations. Operating and maintenance personnel shall fol-
ingintegratedwithsplittingorriffling,endingupwithapproxi-
low the guidelines of safe operating procedures given in
mately100gofmaterialthathasaparticlesizeoflessthan200
currenthandbooksandpublicationsfromtheNationalInstitute
7 ,8 mesh (74 µm).
ofStandardsandTechnology, theU.S.GovernmentPrinting
11.3.1 Briquettes—Mix the sample with a suitable binder.
(See8.2.)Ratiosof10g+1gto20g+1gofsample+binder
arecommon.Grindandblendthesampleandbinderforafixed
Reagent Chemicals, American Chemical Society Specifications, American
time (generally 2 to 4 min in a disk mill). Press the sample-
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
binder mixture into a briquette using a fixed pressure of 140 to
listed by the American Chemical Socie
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.