ASTM E2224-23

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.  
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.  
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 (4). 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 c...
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 cannot replace knowledge, skills, or abilities acquired through education, training, and experience and is to be used in conjunction with professional judgment by individuals with such discipline-specific knowledge, skills, and abilities.  
1.6 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...

General Information

• Status: Historical
• Publication Date: 31-Mar-2023
• ICS: 07.140 - Forensic science
• ICS: 71.040.50 - Physicochemical methods of analysis
• Technical Committee: E30 - Forensic Sciences
• Drafting Committee: E30.01 - Criminalistics

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: E2224 − 23
Standard Guide for
1
Forensic Analysis of Fibers by Infrared Spectroscopy
This standard is issued under the fixed designation E2224; 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 priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.1 Infrared (IR) spectroscopy is a valuable method of fiber
1.7 This international standard was developed in accor-
polymer identification and comparison in forensic examina-
dance with internationally recognized principles on standard-
tions. The use of IR microscopes, coupled with Fourier
ization established in the Decision on Principles for the
transform infrared (FTIR) spectrometers, has greatly simplified
Development of International Standards, Guides and Recom-
the IR analysis of single fibers, thus making the technique
mendations issued by the World Trade Organization Technical
feasible for routine use in the forensic laboratory. This guide
Barriers to Trade (TBT) Committee.
provides basic recommendations and information about IR
spectrometers and accessories, with an emphasis on sampling
2. Referenced Documents
techniques specific to fiber examinations. The particular meth-
2
2.1 ASTM Standards:
od(s) employed by each examiner or laboratory will depend
D123 Terminology Relating to Textiles
upon available equipment, examiner training, sample
E131 Terminology Relating to Molecular Spectroscopy
suitability, and sample size.
E620 Practice for Reporting Opinions of Scientific or Tech-
1.2 This guide is intended for examiners with a basic
nical Experts
knowledge of the theory and practice of IR spectroscopy, as
E1421 Practice for Describing and Measuring Performance
well as experience in the handling and forensic examination of
of Fourier Transform Mid-Infrared (FT-MIR) Spectrom-
fibers. In addition, this guide is to be used in conjunction with
eters: Level Zero and Level One Tests
a broader analytical scheme.
E1459 Guide for Physical Evidence Labeling and Related
1.3 If polymer identification is not readily apparent from
Documentation
optical data alone, an additional method of analysis, such as E1492 Practice for Receiving, Documenting, Storing, and
microchemical tests, melting point, IR spectroscopy, Raman
Retrieving Evidence in a Forensic Science Laboratory
spectroscopy, or pyrolysis gas chromatography, should be
E2228 Guide for Microscopical Examination of Textile Fi-
used. An advantage of IR spectroscopy is that the instrumen-
bers
tation is readily available in most forensic laboratories and the
2.2 Other Documents:
3
technique is minimally destructive.
ISO 17025 Testing and calibration laboratories
1.4 Units—The values stated in SI units are to be regarded
3. Terminology
as standard. No other units of measurement are included in this
3.1 Definitions—For definitions of terms used in this guide,
standard.
refer to Terminologies D123 and E131.
1.5 This standard cannot replace knowledge, skills, or
3.2 Definitions of Terms Specific to This Standard:
abilities acquired through education, training, and experience
3.2.1 aperture, n—an opening in an optical system that
and is to be used in conjunction with professional judgment by
controls the amount of light passing through a system.
individuals with such discipline-specific knowledge, skills, and
abilities.
3.2.2 attenuated total reflection (ATR), n—a method of
spectrophotometric analysis based on the reflection of energy
1.6 This standard does not purport to address all of the
at the interface of two media which have different refractive
safety concerns, if any, associated with its use. It is the
indices and are in intimate contact with each other.
responsibility of the user of this standard to establish appro-
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
1
This guide is under the jurisdiction of ASTM Committee E30 on Forensic contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Sciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved April 1, 2023. Published May 2023. Originally the ASTM website.
3
approved in 2002. Last previous edition approved in 2022 as E2224 – 22. DOI: Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/E2224-23. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United Stat
...

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: E2224 − 22 E2224 − 23
Standard Guide for
1
Forensic Analysis of Fibers by Infrared Spectroscopy
This standard is issued under the fixed designation E2224; 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
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 cannot replace knowledge, skills, or abilities acquired through education, training, and experience and is to be
used in conjunction with professional judgment by individuals with such discipline-specific knowledge, skills, and abilities.
1.6 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.
1.7 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.
2. Referenced Documents
2
2.1 ASTM Standards:
1
This guide 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 May 1, 2022April 1, 2023. Published May 2023. Originally approved in 2002. Last previous edition approved in 20192022 as
E2224 – 19.E2224 – 22. DOI: 10.1520/E2224-22.10.1520/E2224-23.
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 ----------------------
E2224 − 23
D123 Terminology Relating to Textiles
E131 Terminology Relating to Molecular Spectroscopy
E620 Practice for Reporting Opinions of Scientific or Technical Experts
E1421 Practice for Describing and Measuring Performance of Fourier Transform Mid-Infrared (FT-MIR) Spectrometers: Level
Zero and Level One Tests
E1459 Guide for Physical Evidence Labeling and Related Documentation
E1492 Practice for Receiving, Documenting, Storing, and Retrieving Evidence in a Forensic Science Laboratory
E2228 Guide for Microscopical Examination of Textile Fibers
2.2 Other Documents:
3
ISO 17025 Testing and calibration laboratories
3. Terminology
D123 and E131.
3.1 Definitions—For definitions of terms used in this guide, refer to Terminologies
3.2 Definitions of Terms Specific to This Standard:
3.2.1 aperture, n—an opening in an optical system that controls the amount of light passing through a s
...