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ASTM E3309-21

(Guide)

Standard Guide for Reporting of Forensic Primer Gunshot Residue (pGSR) Analysis by Scanning Electron Microscopy/Energy Dispersive X-Ray Spectrometry (SEM/EDS)

Standard Guide for Reporting of Forensic Primer Gunshot Residue (pGSR) Analysis by Scanning Electron Microscopy/Energy Dispersive X-Ray Spectrometry (SEM/EDS)

SIGNIFICANCE AND USE
4.1 This guide is designed to be used by forensic service providers when issuing final reports on pGSR analyses by SEM/EDS.  
4.2 This guide is intended to be used in conjunction with Practice E1588, Practice E620, and the SWGGSR Guide.
SCOPE
1.1 This guide describes the contents of a formal, written technical report expressing the results and interpretation of pGSR particle analysis by SEM/EDS by forensic service providers.  
1.2 This guide is intended for use by competent forensic science practitioners with the requisite formal education, discipline-specific training (see Practices E2917), and demonstrated proficiency to perform forensic casework.  
1.3 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
Published
Publication Date
31-Aug-2021
ICS
07.140 - Forensic science
Technical Committee
E30 - Forensic Sciences
Drafting Committee
E30.01 - Criminalistics
Current Stage
Ref Project

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ASTM E3309-21 - Standard Guide for Reporting of Forensic Primer Gunshot Residue (pGSR) Analysis by Scanning Electron Microscopy/Energy Dispersive X-Ray Spectrometry (SEM/EDS)ASTM E3309-21 - Standard Guide for Reporting of Forensic Primer Gunshot Residue (pGSR) Analysis by Scanning Electron Microscopy/Energy Dispersive X-Ray Spectrometry (SEM/EDS)
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ASTM E3309-21 - Standard Guide for Reporting of Forensic Primer Gunshot Residue (pGSR) Analysis by Scanning Electron Microscopy/Energy Dispersive X-Ray Spectrometry (SEM/EDS)
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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: E3309 − 21 An American National Standard
Standard Guide for
Reporting of Forensic Primer Gunshot Residue (pGSR)
Analysis by Scanning Electron Microscopy/Energy
1
Dispersive X-Ray Spectrometry (SEM/EDS)
This standard is issued under the fixed designation E3309; 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 3. Terminology
1.1 This guide describes the contents of a formal, written
3.1 Definitions:
technical report expressing the results and interpretation of
3.1.1 For definitions of terms that can assist in interpreting
pGSR particle analysis by SEM/EDS by forensic service
this standard, refer to Terminology E1732.
providers.
3.2 Definitions of Terms Specific to This Standard:
1.2 This guide is intended for use by competent forensic
3.2.1 background sample, n—a recovered sample from a
science practitioners with the requisite formal education,
source believed not to have been exposed to pGSR.
discipline-specific training (see Practices E2917), and demon-
3.2.1.1 Discussion—Background samples can be used to
strated proficiency to perform forensic casework.
establish a threshold value.
1.3 This international standard was developed in accor-
3.2.2 candidate particles, n—particle(s) classified by the
dance with internationally recognized principles on standard-
instrument software based on detection of appropriate (as
ization established in the Decision on Principles for the
specified in Practice E1588) constituent elements as potential
Development of International Standards, Guides and Recom-
pGSR.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
3.2.3 confirmed particles, n—particle(s) relocated,
analyzed, and classified by the analyst as pGSR based on
2. Referenced Documents
appropriate (as specified in Practice E1588) constituent ele-
2
2.1 ASTM Standards:
ments and morphology.
E620 Practice for Reporting Opinions of Scientific or Tech-
3.2.4 threshold, n—a value, based on a background sample
nical Experts
study, below which the number of pGSR particles identified
E1732 Terminology Relating to Forensic Science
cannot be distinguished from background levels and thus
E1588 Practice for Gunshot Residue Analysis by Scanning
cannot be reliably interpreted as associated with the discharge
ElectronMicroscopy/EnergyDispersiveX-RaySpectrom-
of a firearm or contact with a source of pGSR.
etry
E2917 Practice for Forensic Science Practitioner Training,
4. Significance and Use
Continuing Education, and Professional Development
Programs
4.1 This guide is designed to be used by forensic service
2.2 Other Documents: providers when issuing final reports on pGSR analyses by
SWGGSR Guide for Primer Gunshot Residue Analysis by SEM/EDS.
Scanning Electron Microscopy/Energy Dispersive X-ray
4.2 This guide is intended to be used in conjunction with
3
Spectrometry
Practice E1588, Practice E620, and the SWGGSR Guide.
1
This guide is under the jurisdiction of ASTM Committee E30 on Forensic
5. Report
Sciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics.
Current edition approved Sept. 1, 2021. Published October 2021. DOI: 10.1520/ 5.1 The report reflects interpretations based on the classifi-
E3309-21.
cation of particle data from the results of instrumental analysis,
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and on associated definitions in Practice E1588, the SWGGSR
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Guide, and the scientific literature.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3
5.2 Pertinent Information—Satisfy the requirements of
Available from Scientific Working Group for Gunshot Residue, https://
www.swggsr.org. Practice E620, Section 4.7, by listing:
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E3309 − 21
5.2.1 The general examinations conducted, including the 5.4.2.2 No (zero) particles confirmed as either characteristic
generic class and type of instrumentation used and the disci- of or consistent with pGSR were detected on the (sample
pline specific technique, methodology, or procedure per- source).
formed. 5.4.2.3 (Numerical value) particles characteristic of pGSR
5.2.1.1 Example Wording—Exhibit 1 was examined by were confirmed but were
...

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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.  
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4.3 Comparisons of X-ray spectra acquired from polymer samples are conducted for source discrimination or potential association.  
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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.  
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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.  
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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.
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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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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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5.2 IR analysis should follow visible and fluorescence comparison microscopy, polarized light microscopy, and ultraviolet (UV)/visible spectroscopy. If no meaningful differences are noted between the known and unknown samples in optical properties, then proceed to IR spectroscopy as the next step in the analytical scheme, as applicable.  
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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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1.1 This practice covers training guidelines for use by forensic laboratory personnel responsible for training forensic examiners that will perform hair examinations, including microscopical comparisons of human hair.  
1.2 Forensic hair examiners are trained in accordance with Practice E2917 and the discipline-specific guidelines (Guide E3316) and criteria within this practice.  
1.3 This practice contains guidelines that include the tasks, goals, and objectives that allow the trainee to acquire the requisite knowledge, skills, and abilities to independently perform casework in the microscopical examination of hair.  
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1.5 This practice addresses training for the microscopical examination of hairs and not the examination of chemical alterations (for example, hair dye) or trace materials on the surface of hairs (for example, hair care products).  
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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.
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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.  
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Standard Guide for Forensic Analysis of Geological Materials by Powder X-Ray Diffraction

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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.  
5.2 Within the analytical scheme of geological materials, XRD analysis is used to: identify the crystalline components within a sample; identify the crystalline components separated from a mixture, typically clay-sized material (see 8.8), or a selected particle class for which additional analysis is needed (see 8.11); or compare two or more samples based on the identified crystalline phases or diffraction patterns (see 11.5).  
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1.1 This guide covers techniques and procedures for the use of powder X-ray diffraction (XRD) in the forensic analysis of geological materials (to include soils, rocks, sediments, and materials derived from them such as concrete), to enable non-consumptive identification of solid crystalline materials present as single components or multi-component mixtures.  
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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).  
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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Standard Guide for Using Scanning Electron Microscopy/Energy Dispersive X-Ray Spectroscopy (SEM/EDS) in Forensic Polymer Examinations

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4.1 This guide is intended to advise and assist the analyst in the preparation of polymer samples (for example, paint and tape) for SEM/EDS, the collection of data by SEM/EDS, and the interpretation of images and data resulting from these analyses.  
4.2 When polymers are constructed as layered materials, SEM/EDS analysis is conducted on each polymeric layer individually. This analysis can be hindered by a non-discernable layer structure (for example, smear, irregular segregation within the layer system).  
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4.3.1 Layer Elucidation—SEM images provide insight into the layer structure of a sample.  
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4.4.1 Comparison of structure, texture, and elemental data.  
4.4.2 Support for results from other instruments (for example, the presence of calcium, oxygen, and carbon in the EDS spectrum obtained from discrete particles indicates the presence of calcium carbonate as observed in an infrared spectrum). Refer to Guides E2937 and E3085 for further details.  
4.4.3 Significance of results given the presence of certain elements, layer structures, or textures.
SCOPE
1.1 This guide covers recommended techniques and procedures intended for use by forensic laboratory personnel that perform SEM/EDS analyses on polymer samples.  
1.2 This guide describes various techniques and procedures used in the SEM/EDS analysis of polymers that include sample handling and preparation, instrument operating conditions, and spectral data collection, evaluation and interpretation.  
1.3 The theoretical aspects of many of the topics presented can be found in texts such as Scanning Electron Microscopy and X-ray Microanalysis (1).2  
1.4 This guide is intended to be applied within the scope of a broader analytical scheme (for example, Guides E1610, E3260) for the forensic analysis of a polymer sample. An SEM/EDS analysis can provide additional information regarding the potential relationships between the sources of polymeric materials.  
1.5 This guide is intended for use by competent forensic science practitioners with the requisite formal education, discipline-specific training (see Practices E2917, E3233, and E3234), and demonstrated proficiency to perform forensic casework.  
1.6 The values stated in SI units are to be regarded as standard. Other units of measurement are included in this standard where applicable as a result of common usage (for example, keV).  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.8 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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  • Guide
    8 pages
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ASTM
ASTM E3296-22(Guide)
Standard Guide for Using Pyrolysis Gas Chromatography and Pyrolysis Gas Chromatography-Mass Spectrometry in Forensic Polymer Examinations

SIGNIFICANCE AND USE
4.1 This guide provides guidance in the selection of appropriate sample preparation methods and instrumental parameters for the analysis, comparison, or identification of various polymeric materials by PGC and PGC/MS.  
4.1.1 PGC/MS can differentiate between classes of fibers (for example, acrylic, polyester, nylon) and within classes of fibers (for example, acrylics) (1-3).5  
4.1.2 Paint binders are differentiated based upon the variety of monomers used in paint formulations which could be difficult to identify by other analytical techniques. In addition, some additives can be detected or identified.  
4.1.3 Differentiation can be achieved by the separation and identification of organic components in the adhesive portion of tapes (4, 5) and in the backings of electrical tapes (6).  
4.1.4 PGC/MS can provide additional discrimination for other types of polymers such as automotive lenses, automotive body fillers, cosmetics, plastics, and rubbers (7-9).  
4.2 Pyrolysis breaks a large molecule into many smaller molecules in a reproducible fashion through the breaking of bonds by means of the application of thermal energy. Analytical pyrolysis is used to provide chemical information on organic-containing solids that cannot be dissolved or otherwise introduced into a chromatographic system. It is also used to analyze and compare solvents bound in a solid material (such as tape adhesives) (10). When analyzed using a separation technique such as gas chromatography, the smaller molecules produced through the action of pyrolysis form a pattern of separated fragments. Mass and structural information indicative of the original molecule are also available when a mass spectral detector is used.  
4.3 Although a destructive method, and therefore often placed at the end of an analytical scheme, the pyrograms produced from different polymer compositions form characteristic patterns that are useful for both identification of polymer type and comparisons between samples (4, 6...
SCOPE
1.1 This guide covers information and recommendations for the selection and application of various PGC and PGC/MS procedures and methods in the forensic examination of polymeric materials (for example, fibers, paint, tape). PGC and PGC/MS methods are used for the identification and comparison of the organic components of these materials. Refer to Practice D3452 for further information on the preparation of the pyrolysis system for polymeric analyses.  
1.2 This guide is to be used in conjunction with a broader analytical scheme such as Guides E1610 or E3260, or the SWGMAT Forensic Fiber Examination Guidelines.  
1.3 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.  
1.4 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 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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