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ASTM E3295-22

(Guide)

Standard Guide for Using Micro X-Ray Fluorescence (μ-XRF) in Forensic Polymer Examinations

Standard Guide for Using Micro X-Ray Fluorescence (μ-XRF) in Forensic Polymer Examinations

SIGNIFICANCE AND USE
4.1 µ-XRF is a nondestructive qualitative elemental analysis technique used for polymers. It involves excitation of a sample by an X-ray source resulting in the emission of characteristic X-rays detected using an energy dispersive X-ray detector. Results are displayed simultaneously as a spectrum of intensity as a function of energy for elements of atomic number 11 or greater.  
4.2 µ-XRF enables the determination of the elemental composition of a specimen and can be utilized for comparisons of components of polymeric materials (for example, tape backings, tape adhesives, paint layers).  
4.3 Comparisons of X-ray spectra acquired from polymer samples are conducted for source discrimination or potential association.  
4.4 Quantitative processes for µ-XRF analysis are available but are not used for polymer analyses because of the lack of prepared polymer standard reference samples.  
4.5 In general, information available from a heterogeneous specimen diminishes as its size is reduced or its condition degrades, which lessens its likelihood of being representative of the source material.  
4.6 µ-XRF data collected from polymers is limited to specific information (for example, elements detected, relative elemental abundance); additional analytical procedures are required to further characterize and identify the chemical composition of the polymer sample.  
4.7 Limitations of µ-XRF include the inability to detect some elements in trace concentrations, the inability to analyze individual particles, the potential interference related to the penetration depth of the beam relative to the sample thickness, the inability to resolve the peaks of some elements (for example, Ba Lα / Ti Kα), and the potential for discoloration of some materials due to exposure to radiation.
SCOPE
1.1 This guide covers recommended techniques and procedures intended for use by forensic laboratory personnel that perform µ-XRF analysis of polymer samples.  
1.2 This guide describes various techniques and procedures used in the µ-XRF analysis of polymers that include sample handling and preparation, instrument operating conditions, and spectral data collection, evaluation and interpretation.  
1.3 This guide describes the application of µ-XRF systems equipped with either mono- or poly- capillary optics and an energy dispersive X-ray detector (EDS).  
1.4 This guide is intended to be applied within the scope of a broader analytical scheme (for example, Guide E1610, Guide E3260) for the forensic analysis of a polymer sample (1-6).2 A µ-XRF analysis can provide additional information regarding the potential relationships between the sources of polymeric materials.  
1.5 The fundamental aspects of the composition and manufacture of polymeric materials or theory of X-ray fluorescence can be found in various texts (7-18).  
1.6 This standard is intended for use by competent forensic science practitioners with the requisite formal education, discipline-specific training (see Practices E2917, E3233, E3234), and demonstrated proficiency to perform forensic casework.  
1.7 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.8 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.9 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.

General Information

Status
Historical
Publication Date
31-Oct-2022
ICS
07.140 - Forensic science
Technical Committee
E30 - Forensic Sciences
Drafting Committee
E30.01 - Criminalistics
Current Stage
Ref Project

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ASTM E3295-22 - Standard Guide for Using Micro X-Ray Fluorescence (μ-XRF) in Forensic Polymer ExaminationsASTM E3295-22 - Standard Guide for Using Micro X-Ray Fluorescence (μ-XRF) in Forensic Polymer Examinations
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ASTM E3295-22 - Standard Guide for Using Micro X-Ray Fluorescence (μ-XRF) in Forensic Polymer Examinations
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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: E3295 − 22 An American National Standard
Standard Guide for
Using Micro X-Ray Fluorescence (µ-XRF) in Forensic
1
Polymer Examinations
This standard is issued under the fixed designation E3295; 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
Micro X-ray fluorescence spectrometry (µ-XRF) is one technique in an analytical scheme that can
provide information regarding potential relationships between the sources of polymeric materials.
1. Scope 1.8 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This guide covers recommended techniques and proce-
responsibility of the user of this standard to establish appro-
dures intended for use by forensic laboratory personnel that
priate safety, health, and environmental practices and deter-
perform µ-XRF analysis of polymer samples.
mine the applicability of regulatory limitations prior to use.
1.2 This guide describes various techniques and procedures
1.9 This international standard was developed in accor-
used in the µ-XRF analysis of polymers that include sample
dance with internationally recognized principles on standard-
handling and preparation, instrument operating conditions, and
ization established in the Decision on Principles for the
spectral data collection, evaluation and interpretation.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
1.3 This guide describes the application of µ-XRF systems
Barriers to Trade (TBT) Committee.
equipped with either mono- or poly- capillary optics and an
energy dispersive X-ray detector (EDS).
2. Referenced Documents
3
1.4 This guide is intended to be applied within the scope of
2.1 ASTM Standards:
a broader analytical scheme (for example, Guide E1610, Guide
E620 Practice for Reporting Opinions of Scientific or Tech-
2
E3260) for the forensic analysis of a polymer sample (1-6). A
nical Experts
µ-XRF analysis can provide additional information regarding
E1492 Practice for Receiving, Documenting, Storing, and
the potential relationships between the sources of polymeric
Retrieving Evidence in a Forensic Science Laboratory
materials.
E1610 Guide for Forensic Paint Analysis and Comparison
E1732 Terminology Relating to Forensic Science
1.5 The fundamental aspects of the composition and manu-
facture of polymeric materials or theory of X-ray fluorescence E2917 Practice for Forensic Science Practitioner Training,
Continuing Education, and Professional Development
can be found in various texts (7-18).
Programs
1.6 This standard is intended for use by competent forensic
E2926 Test Method for Forensic Comparison of Glass Using
science practitioners with the requisite formal education,
Micro X-ray Fluorescence (µ-XRF) Spectrometry
discipline-specific training (see Practices E2917, E3233,
E3233 Practice for Forensic Tape Analysis Training Program
E3234), and demonstrated proficiency to perform forensic
E3234 Practice for Forensic Paint Analysis Training Pro-
casework.
gram
1.7 Units—The values stated in SI units are to be regarded
E3260 Guide for Forensic Examination and Comparison of
as standard. No other units of measurement are included in this
Pressure Sensitive Tapes
4
standard.
2.2 SWGMAT Documents:
SWGMAT Trace Evidence Recovery Guidelines
SWGMAT Trace Evidence Quality Assurance Guidelines
1
This guide is under the jurisdiction of ASTM Committee E30 on Forensic
3
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 Nov. 1, 2022. Published February 2023. DOI: 10.1520/ contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
E3295-22. Standards volume information, refer to the standard’s Document Summary page on
2
The boldface numbers in parentheses refer to the list of references at the end of the ASTM website.
4
this standard. Available from https://www.asteetrace.org/subtrace.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E3295 − 22
5
2.3 ISO Standard: 3.2.9.1 Discussion—Each element has characteristic ener-
ISO/IEC 17025 Laboratory Competence gies of transitions of electrons between shells.
3.2.10 live time, n—the time during which an energy dis-
3. Terminology
persive X-ray spectrometer is available to accept and process
3.1 Definitions—The terms defined relate specifically to
incoming X-ra
...

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4.1 The design and configuration of an audio laboratory, as well as the maintenance of equipment, are factors that must be considered to ensure an optimal environment to produce the best results. This guide is intended to provide general guidance for laboratory setup and maintenance.  
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5.1 The overarching goals of the forensic analysis of geological materials include (A) identification of an unknown material (see 11.3), (B) analysis of soils, sediments, or rocks to restrict their possible geographic origins as part of a provenance analysis (see 11.4), and (C) comparison of two or more samples to assess if they could have originated from the same source or to exclude a common source based on observation of exclusionary differences (see 11.5). XRD is only one analytical method that can be applied to the evidentiary samples in service of these distinct goals. Guidance for the analysis of forensic geological materials can be found in Refs (2-4).  
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5.2.2 The most common forensic applications of XRD to geological materials are (A) identification or confirmation of a selected phase or fraction of a sample (see 8.12), (B) identification of minerals in the clay-sized fractions of soils (see 8.8), and (C) identification of the phases of the hydrated cement component of concrete or mortar.  
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1.3 Units—The values stated in SI units are to be regarded as standard. Other units are avoided, in general, but there is a long-standing tradition of expressing X-ray wavelengths and lattice spacing in units of Ångströms (Å). One Ångström = 10–10 meter (m) = 0.1 nanometer (nm).  
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4.1 A training program provides the theoretical foundation and practical skills necessary for a trainee to become a qualified forensic hair examiner.  
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4.1 Color is an easily observable characteristic of soils and is integral to the taxonomic classifications of soils (6-8); factors including parent material, hydrology, vegetation, and extent of soil weathering, can affect soil color, making color a valuable diagnostic tool for forensic examination purposes.  
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Standard Guide for Forensic Analysis of Fibers by Infrared Spectroscopy

SIGNIFICANCE AND USE
5.1 This guide is designed to assist an examiner in the selection of appropriate sample preparation methods for the analysis, comparison, and identification of fibers using IR spectroscopy. IR spectroscopy can provide additional compositional information than is obtained using polarized light microscopy alone. The extent to which IR spectral comparison is conducted will vary with specific sample and case evaluations.  
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Note 1: IR analysis generally follows the aforementioned techniques since sample preparation (for example, flattening) irreversibly changes fiber morphology.  
5.3 IR spectroscopy should be conducted before dye extraction for chromatography due to the semi-destructive nature of the extraction technique. Because of the large number of sub-generic classes, forensic examination of acrylic and modacrylic fibers is likely to benefit significantly from IR spectral analysis (5). Useful distinctions between subtypes of nylon and polyester fibers can also be made by IR spectroscopy.  
5.4 IR spectroscopy can provide molecular information regarding major organic and inorganic components. Components in lesser amounts are typically more difficult to identify. Reasons for this include interference of the absorption bands of the major components with the less-intense bands of minor components, and sensitivity issues whereby the minor components are present at concentrations below the detection limits of the instrument.  
5.5 Fiber samples are prepared and mounted for microscopical IR analysis by a variety of techniques. IR spectra of fibers are obtained using an IR spectrometer coupled with an IR microscope, ATR, or diamond...
SCOPE
1.1 Infrared (IR) spectroscopy is a valuable method of fiber polymer identification and comparison in forensic examinations. The use of IR microscopes, coupled with Fourier transform infrared (FTIR) spectrometers, has greatly simplified the IR analysis of single fibers, thus making the technique feasible for routine use in the forensic laboratory. This guide provides basic recommendations and information about IR spectrometers and accessories, with an emphasis on sampling techniques specific to fiber examinations. The particular method(s) employed by each examiner or laboratory will depend upon available equipment, examiner training, sample suitability, and sample size.  
1.2 This guide is intended for examiners with a basic knowledge of the theory and practice of IR spectroscopy, as well as experience in the handling and forensic examination of fibers. In addition, this guide is to be used in conjunction with a broader analytical scheme.  
1.3 If polymer identification is not readily apparent from optical data alone, an additional method of analysis, such as microchemical tests, melting point, IR spectroscopy, Raman spectroscopy, or pyrolysis gas chromatography, should be used. An advantage of IR spectroscopy is that the instrumentation is readily available in most forensic laboratories and the technique is minimally destructive.  
1.4 Units—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 is intended for use by competent forensic science practitioners with the requisite formal education, discipline-specific training (see Practice E2917), and demonstrated proficiency to perform forensic casework.  
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Standard Guide for Forensic Examination of Dyes in Textile Fibers by Thin-Layer Chromatography

SIGNIFICANCE AND USE
5.1 TLC is an inexpensive and simple technique that could be used to complement other analytical techniques within a general analytical scheme related to forensic fiber examination.  
5.2 Consider the forensic analysis of fiber colorants using TLC for single fiber comparisons only when the sample size is adequate (that is, enough colorant can be extracted for analysis) and it is not possible to discriminate between the fibers of interest using other techniques, such as comparison microscopy and MSP. Larger fibrous units (for example, thread or tuft) can be treated as an individual sample if determined to be homogeneous. Do not treat fibers that cannot be directly related to each other as a collective sample for the purposes of TLC.  
5.3 The extraction procedures carried out prior to TLC analysis can provide useful information about dye classification. TLC can provide qualitative information about dye components. Similar colors made up of different dye components can be differentiated using this technique. The application of TLC may serve to discriminate between fibers or it may support the possibility of fibers sharing a common source.  
5.4 TLC can be prohibitively difficult or undesirable in some circumstances. Short lengths of fibers or pale-colored fibers can lack adequate amounts of colorant necessary to be examined by TLC. Dye extraction from some fibers can be impossible (2, 3). Some fiber types do not truly extract, but change or lose color. Reactive dyes are covalently bonded to the fiber and typically cannot be removed by conventional extraction methods, but can be released from cotton and wool by disrupting the fiber by enzymatic or chemical digestion, respectively (1). The desire to preserve evidence from deleterious change or for possible analysis by another examiner can preclude removing the color or employing a destructive method for analysis.
SCOPE
1.1 This guide is intended as an overview of the Thin-Layer Chromatography (TLC) of fiber colorants (or individual dye components) present in dyed fibers. It is intended to be applied within the scope of a broader analytical scheme for the forensic analysis of fiber samples. TLC could provide information that cannot be obtained through other color analyses (such as microspectrophotometry (MSP)) (1).2  
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Standard Guide for Forensic Examination of Fabrics and Cordage

SIGNIFICANCE AND USE
5.1 The construction, composition, and color of textiles contain useful comparative characteristics for forensic examinations. Textiles are observed in a variety of constructions: woven, knit, nonwoven, or in combination. The range of colors in which textiles are offered in the marketplace is vast and constantly changing due to styles and seasons.  
5.2 A complete characterization of the fabrics, including their construction, and other materials used in the assemblage of a textile (for example, sewing thread) is a critical component of a comprehensive forensic fabric or cordage examination.
SCOPE
1.1 This guide is intended to assist individuals and laboratories that conduct examinations of fabrics and cordage for the purposes of analyzing and comparing types of fabric, cordage and damage. A complete characterization of the fabrics, including their construction and other materials used in the assemblage of a textile (for example, sewing thread), is a critical component of a comprehensive forensic fabric or cordage examination.  
1.2 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard is intended for use by competent forensic science practitioners with the requisite formal education, discipline-specific training (see Practice E2917), and demonstrated proficiency to perform forensic case work  
1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 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.

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    6 pages
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  • Guide
    6 pages
    English language
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ASTM
ASTM E3316-22(Guide)
Standard Guide for Forensic Examination of Hair by Microscopy

SIGNIFICANCE AND USE
4.1 A microscopical hair examination is conducted to determine if the item is a hair; from a human; from a particular somatic region; characteristic of a broad geographically-assigned ancestral group; characteristic of a particular growth phase; damaged; symptomatic of disease, condition, or disorder; forcibly removed; chemically altered (for example, dyed or bleached); suitable for microscopical comparison; suitable for DNA analysis; and similar to or different from a known sample (4-9).  
4.2 Most often, hairs from the head and pubic regions of the body are used for microscopical comparisons. There is usually more interpersonal variability in the characteristics of head and pubic hairs than in the hairs from other somatic regions. Head hairs usually show more interpersonal variation than pubic hairs. Hairs from other somatic regions may also be compared, but these comparisons are usually limited and less frequently conducted. Accordingly, this guide primarily considers human head and pubic hair comparisons.  
4.3 Microscopical hair comparisons are not a means of individualization (10). This limitation is to be stated in any communication (for example, reports, testimony) when an association is reported.  
4.4 Additional analyses can be performed on hairs that have been chemically altered (for example, dyed hair) or have trace materials on the surface (for example, glitter). Such techniques are beyond the scope of this document.
SCOPE
1.1 This guide covers procedures used by forensic laboratory personnel in the forensic examination of hair by microscopy, including microscopical comparisons and classification of hair samples.  
1.2 This guide addresses instrument setup, hair collection, sample handling techniques, and the use of various microscopes in the examination and comparison of hair.  
1.3 This guide addresses the benefit of following microscopical examinations with DNA analysis.  
1.4 This standard is intended for use by competent forensic science practitioners with the requisite formal education, discipline-specific training (see Practice E2917), and demonstrated proficiency to perform forensic casework.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 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.

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    9 pages
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