ASTM E2926-17

Standard Test Method for Forensic Comparison of Glass Using Micro X-ray Fluorescence (µ-XRF) Spectrometry

SIGNIFICANCE AND USE
4.1 µ-XRF provides a means of simultaneously detecting major, minor, and trace elemental constituents in small glass fragments such as those frequently examined in forensic case work. It can be used at any point in the analytical scheme without concern for changing sample shape or sample properties, such as RI, due to its totally nondestructive nature.  
4.2 Limits of detection (LOD) are dependent on several factors, including instrument configuration and operating parameters, sample thickness, and atomic number of the individual elements. Typical LODs range from parts per million (µgg-1) to percent (%).  
4.3 µ-XRF provides simultaneous qualitative analysis for elements having an atomic number of eleven or greater. This multi-element capability permits detection of elements typically present in glass such as magnesium (Mg), silicon (Si), aluminum (Al), calcium (Ca), potassium (K), iron (Fe), titanium (Ti), strontium (Sr), and zirconium (Zr), as well as other elements that may be detectable in some glass by µ-XRF (for example, molybdenum (Mo), selenium (Se), or erbium (Er)) without the need for a predetermined elemental menu.  
4.4 µ-XRF comparison of glass fragments provides additional discrimination power beyond that of RI or density comparisons, or both, alone.  
4.5 The method precision should be established in each laboratory for the specific conditions and instrumentation in that laboratory.  
4.6 When using small fragments having varying surface geometries and thicknesses, precision deteriorates due to take-off-angle and critical depth effects. Flat fragments with thickness greater than 1.5 mm do not suffer from these constraints, but are not always available as questioned specimens received in casework. As a consequence of the deterioration in precision for small fragments and the lack of appropriate calibration standards, quantitative analysis by µ-XRF is not typically used.  
4.7 Appropriate sampling techniques should be used to account for natural h...
SCOPE
1.1 This test method is for the determination of major, minor, and trace elements present in glass fragments. The elemental composition of a glass fragment can be measured through the use of µ-XRF analysis for comparisons of glass.  
1.2 This test method covers the application of µ-XRF using mono- and poly- capillary optics, and an energy dispersive X-ray detector (EDS).  
1.3 This test method does not replace knowledge, skill, ability, experience, education, or training and should be used in conjunction with professional judgment.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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

• Status: Published
• Publication Date: 31-Jan-2017
• ICS: 07.140 - Forensic science
• ICS: 81.040.10 - Raw materials and raw glass
• Technical Committee: E30 - Forensic Sciences
• Drafting Committee: E30.01 - Criminalistics

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E2926 − 17 An American National Standard
Standard Test Method for
Forensic Comparison of Glass Using Micro X-ray
1
Fluorescence (µ-XRF) Spectrometry
This standard is issued under the fixed designation E2926; 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.
INTRODUCTION
One objective of a forensic glass examination is to compare glass specimens to determine if they
canbediscriminatedusingtheirphysical,opticalorchemicalproperties(forexample,color,refractive
index (RI), density, elemental composition). If the specimens are distinguishable, except for
acceptable and explainable variations, in any of these observed and measured properties, it may be
concluded that they did not originate from the same source of broken glass. If the specimens are
indistinguishable in all of these observed and measured properties, the possibility that they originated
from the same source of glass cannot be eliminated. The use of an elemental analysis method such as
micro X-ray fluorescence spectrometry (µ-XRF) yields high discrimination among sources of glass.
1. Scope 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This test method is for the determination of major,
E177 Practice for Use of the Terms Precision and Bias in
minor, and trace elements present in glass fragments. The
ASTM Test Methods
elemental composition of a glass fragment can be measured
E2330 Test Method for Determination of Concentrations of
through the use of µ-XRF analysis for comparisons of glass.
Elements in Glass Samples Using Inductively Coupled
1.2 This test method covers the application of µ-XRF using Plasma Mass Spectrometry (ICP-MS) for Forensic Com-
mono- and poly- capillary optics, and an energy dispersive parisons
X-ray detector (EDS).
3. Summary of Test Method
1.3 This test method does not replace knowledge, skill,
3.1 µ-XRF is a nondestructive elemental analysis technique
ability,experience,education,ortrainingandshouldbeusedin
based on the emission of characteristic X-rays following the
conjunction with professional judgment.
excitation of the specimen by an X-ray source using capillary
optics. Simultaneous multi-elemental analysis is typically
1.4 The values stated in SI units are to be regarded as
achieved for elements of atomic number eleven or greater.
standard. No other units of measurement are included in this
standard. 3.2 Glass fragments usually do not require sample prepara-
tion prior to analysis by µ-XRF. Cleaning of specimens may be
1.5 This standard does not purport to address all of the
performed to remove any surface debris.
safety concerns, if any, associated with its use. It is the
3.3 Specimens are mounted and placed into the instrument
responsibility of the user of this standard to establish appro-
chamber and subjected to an X-ray beam. The characteristic
priate safety and health practices and determine the applica-
X-rays emitted by the specimen are detected using an energy
bility of regulatory limitations prior to use.
dispersive X-ray detector and displayed as a spectrum of
energy versus intensity.
3.4 Qualitative analysis is accomplished by identifying
elements present in the specimen based on their characteristic
X-ray energies.
1
ThistestmethodisunderthejurisdictionofASTMCommitteeE30onForensic
2
Sciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 1, 2017. Published February 2017. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2013. Last previous edition approved in 2013 as E2926 – 13. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E2926-17. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E2926 − 17
3.5 Semi-quantitative analysis is accomplished by compar- capability and less analysis time. LA-ICP-MS drawbacks are
ing the relative area under the peaks of characteristic X-rays of greater instrument cost and complexity of operation.
certain elements.
4.10 Scanning Electron Microscopy with EDS (SEM-EDS)
3.6 Spectral and elemental ratio comparisons of the glass is also available for elemental analysis, but it is of limited use
for forensic glass source discrimination due to poor det
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E2926 − 13 E2926 − 17
Standard Test Method for
Forensic Comparison of Glass Using Micro X-ray
1
Fluorescence (μ-XRF) Spectrometry
This standard is issued under the fixed designation E2926; 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.
INTRODUCTION
One objective of a forensic glass examination is to compare glass specimens to determine if they
can be discriminated using their physical, optical or chemical properties (for example, color, refractive
index (RI), density, elemental composition). If the specimens are distinguishable, except for
acceptable and explainable variations, in any of these observed and measured properties, it may be
concluded that they did not originate from the same source of broken glass. If the specimens are
indistinguishable in all of these observed and measured properties, the possibility that they originated
from the same source of glass cannot be eliminated. The use of an elemental analysis method such as
micro X-ray fluorescence spectrometry (μ-XRF) yields high discrimination among sources of glass.
1. Scope
1.1 This test method is for the determination of major, minor, and trace elements present in glass fragments. The elemental
composition of a glass fragment can be measured through the use of μ-XRF analysis for comparisons of glass.
1.2 This test method covers the application of μ-XRF using mono- and poly- capillary optics, and an energy dispersive X-ray
detector (EDS).
1.3 This test method does not replace knowledge, skill, ability, experience, education, or training and should be used in
conjunction with professional judgment.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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.
2. Referenced Documents
2
2.1 ASTM Standards:
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E2330 Test Method for Determination of Concentrations of Elements in Glass Samples Using Inductively Coupled Plasma Mass
Spectrometry (ICP-MS) for Forensic Comparisons
3. Summary of Test Method
3.1 μ-XRF is a nondestructive elemental analysis technique based on the emission of characteristic X-rays following the
excitation of the specimen by an X-ray source using capillary optics. Simultaneous multi-elemental analysis is typically achieved
for elements of atomic number eleven or greater.
3.2 Glass fragments usually do not require sample preparation prior to analysis by μ-XRF. Cleaning of specimens may be
performed to remove any surface debris.
1
This test method is under the jurisdiction of ASTM Committee E30 on Forensic Sciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics.
Current edition approved June 15, 2013Feb. 1, 2017. Published July 2013February 2017. Originally approved in 2013. Last previous edition approved in 2013 as E2926
– 13. DOI: 10.1520/E2926-13.10.1520/E2926-17.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. 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
1

---------------------- Page: 1 ----------------------
E2926 − 17
3.3 Specimens are mounted and placed into the instrument chamber and subjected to an X-ray beam. The characteristic X-rays
emitted by the specimen are detected using an energy dispersive X-ray detector and displayed as a spectrum of energy versus
intensity.
3.4 Qualitative analysis is accomplished by identifying elements present in the specimen based on their characteristic X-ray
energies.
3.5 Semi-quantitative analysis is accomplished by comparing the relative area under the peaks of characteristic X-rays of certain
elements.
3.6 Spectral and elemental ratio comparisons of the glass specimens are conducted for source discrimination or association.
4. Significance and Use
4.1 μ-XRF provides a means of sim
...