ASTM E3253-21

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: E3253 − 21 An American National Standard
Standard Practice for
Establishing an Examination Scheme for Intact Explosives
This standard is issued under the fixed designation E3253; 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 2. Referenced Documents
2.1 ASTM Standards:
1.1 This practice covers the evaluation, selection, and ap-
E620 Practice for Reporting Opinions of Scientific or Tech-
plication of techniques to establish examination schemes for
nical Experts
use by forensic explosives examiners to identify intact (unex-
E860 Practice for Examining And Preparing Items That Are
ploded) low and high explosives.Afoundation for a consistent
Or May Become Involved In Criminal or Civil Litigation
approach to the analysis of intact explosives is provided.
E1732 Terminology Relating to Forensic Science
Methods for the development of identifying information that
E2917 Practice for Forensic Science Practitioner Training,
follows an efficient order of testing are described.
Continuing Education, and Professional Development
1.2 This practice establishes requirements for the use of
Programs
visual, physical, analytical, and instrumental techniques that
E2998 Practice for Characterization and Classification of
provide structural and chemical information for an identifica-
Smokeless Powder
tion of a high or low explosive material.
E2999 Test Method for Analysis of Organic Compounds in
1.3 Techniques used in the examination of explosives in- Smokeless Powder by Gas Chromatography-Mass Spec-
clude visual and microscopical inspection, physical
trometry and Fourier Transform Infrared Spectroscopy
characterization, ignition susceptibility testing, chemical and E3196 Terminology Relating to the Examination of Explo-
spot testing, and instrumental methods.
sives
E3255 Practice for Quality Assurance of Forensic Science
1.4 The minimum requirements for identification of com-
Service Providers Performing Forensic ChemicalAnalysis
monly encountered explosives and explosive materials are
2.2 Other Resources:
listed.
Technical/Scientific Working Group for Fire and Explosion
1.5 This standard is intended for use by competent forensic
Analysis (T/SWGFEX) Suggested Guide for Explosive
science practitioners with the requisite formal education,
Analysis Training
discipline-specific training (see Practice E2917), and demon-
3. Terminology
strated proficiency to perform forensic casework (refer to the
T/SWGFEX Suggested Guide for Explosives Analysis Train-
3.1 Definitions—For definitions of terms used in this stan-
ing).
dard other than those listed in 3.2, see Terminology E1732 and
Terminology E3196.
1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.2 Definitions of Terms Specific to This Standard:
responsibility of the user of this standard to establish appro-
3.2.1 detection, n—an analytical signal from a recognized
priate safety, health, and environmental practices and deter-
analyte was generated and can be tentatively identified (1).
mine the applicability of regulatory limitations prior to use.
3.2.2 identification, n—assigning an analyte (analytical sig-
1.7 This international standard was developed in accor-
nal) to one of the set of known individual chemical compounds
dance with internationally recognized principles on standard-
or to a group/class of compounds.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
mendations issued by the World Trade Organization Technical
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Barriers to Trade (TBT) Committee.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Available from National Institute of Standards and Technology (NIST), 100
Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, https://www.nist.gov/
This practice is under the jurisdiction of ASTM Committee E30 on Forensic system/files/documents/2018/09/21/twgfex_suggest_guide_for_explosive_analysis
Sciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics. _training.pdf.
Current edition approved Nov. 1, 2021. Published December 2021. DOI: The boldface numbers in parentheses refer to the list of references at the end of
10.1520/E3253-21. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E3253 − 21
3.2.2.1 Discussion—Identification of individual compounds analyses performed to provide further discrimination and
can be required to identify an analyzed sample as one of a characterization of samples.
definite kind/type/grade/brand of products, material
6. Analytical Scheme for Examination of Intact
compositions, formulations, etc. (1).
Explosives
3.2.3 ignition susceptibility test, IST, n—a qualitative and
6.1 The identification of an intact explosive is accomplished
destructive test in which a small amount of sample is exposed
by a variety of analytical techniques (2-5). A combination of
to a flame or heat.
multiple techniques and methodologies that provides structural
3.2.3.1 Discussion—Determining the reactivity of the
and chemical information about an explosive, could be re-
sample is useful in terms of initial characterization and safe
quired to make an identification. The examiner shall be
handling.
familiarwiththelimitationsandapplicabilityofeachtechnique
3.2.4 intact explosive, n—an explosive that has not under-
used (refer to T/SWGFEX Suggested Guide for Explosives
gone decomposition due to deflagration or detonation and
Analysis Training).
generally has a discernible morphology.
6.2 Some of the techniques listed below can alter or destroy
3.2.4.1 Discussion—Intact explosives can be present in
the sample. For example, an ignition susceptibility test (6.6)
large (grams) or small (single particle) quantities. Post-blast
consumes the material, solvent extraction alters the
explosive residues can contain both combustion products and
composition, and grinding a sample for X-ray powder diffrac-
intact explosive material.
tion (6.13) changes particle morphology. A portion of the
original sample should be preserved for potential future exami-
4. Summary of Practice
nation; however, preservation will depend on the submitted
sample size, sample preparation and analytical techniques
4.1 Multiple techniques and methods are used in the iden-
used.
tification of explosives.
6.3 Areview of the general technique descriptions, listed in
4.2 Examination of suspected explosives starts with macro-
6.4 – 6.13 and outlined in Fig. 1, provides guidance for the
scopical and microscopical observations and, when
selection of appropriate methods. More detailed schemes for
appropriate, an ignition susceptibility test (IST). The interpre-
theexaminationofintactexplosivesareoutlinedinFig.2(Low
tation of these initial tests requires that the examiner has a
Explosives) and Fig. 3 (High Explosives). The major steps in
working knowledge of explosives. While characteristics ob-
Fig.2andFig.3arenumberedtocorrespondtothediscussions
served by visual examination and IST results can indicate an
presented in this standard (for example 6.6, Ignition Suscepti-
explosive, it is necessary to use additional analytical tech-
bility Test and 7.2, Black Powder). If limited sample is
niques to identify the suspected explosive compound or its key
available, use an analytical scheme that yields the most
components.
information and consumes the least amount of sample. Fig. 2
and Fig. 3 do not imply that other examinations should be
5. Significance and Use
excluded or that the order of the procedures in the figures is
5.1 This practice is designed to assist the forensic explo-
predetermined.
sives examiner in selecting and organizing an analytical
6.4 Visual/Macro and Microscopical Exams:
scheme for identifying intact explosives. The amount and
6.4.1 Begin with a review of the information submitted with
conditionofthesample,aswellastheavailabilityofapplicable
the evidence, including the condition of the packaging and
instrumental techniques, will determine the selected analytical
labeling, and document any potential for cross-contamination
scheme.
between samples.
5.2 The forensic explosives examiner considers relevant
6.4.1.1 Record any potential for cross-contamination or
issuesaboutthecaseinvestigationandsubmitteditems,suchas
discrepancies and take this into account in the final evaluation
sample size, complexity and condition, environmental effects,
of the analytical data.
and collection methods used. Considerations include test
6.4.2 Conduct a visual and stereo microscopical assessment
methods, sample preparation schemes, test sequences, and
of each item, prior to when the packaging permits, and after
acceptable degrees of sample alteration and consumption that
opening the evidence packaging. Provide a written description
will be different for each case submission.
of the general condition, size, shape, and color of each sample
and photograph when possible.
5.3 This practice provides the minimum criteria for identi-
6.4.2.1 This preliminary assessment provides information
fying explosive material. The examiner determines an analyti-
for the selection of an analytical scheme and can identify
cal scheme that uses techniques to correctly identify the
complexities in the review of analytical data obtained.
material, which could include oxidizers, fuels, binders, and
6.4.3 The processing of intact explosives should be sepa-
detection agents.
rated in space from residue evidence samples to prevent
5.4 This practice is used in conjunction with the referenced
incidental contamination. If space does not allow for this, then
documents.
process intact explosives and residue evidence separately by
5.5 This practice does not attempt to address all the issues time. Ensure appropriate precautions are in place to prevent
regarding sample analyses. There could be additional tests or contamination (6-13).
E3253 − 21
FIG. 1 General Scheme for Intact Explosives Examination
6.5 Sample Preparation: 6.7 Chemical Spot (color) Tests:
6.5.1 Use sample preparation techniques, such as manual 6.7.1 Use chemical spot tests to screen for the presence of
separation,sieving,grinding,orextraction (2),forpowdersand explosives or explosive components (4, 14).
powder mixtures. 6.7.1.1 Conduct chemical spot tests contemporaneously
6.5.1.1 These preparation techniques result in separation with the appropriate positive and negative controls.
and isolation of individual particles or explosive components
6.8 Polarized Light Microscopy (PLM):
for instrumental analysis.
6.8.1 Determine optical crystallographic properties to iden-
6.6 Ignition Susceptibility Test (IST): tify explosive compounds and components from low explosive
6.6.1 Use an IST to determine if an unknown sample will mixtures such as black powder, flash powder and black powder
ignite easily. Conduct the test on a safe and suitable sample substitutes, and high explosives such as ANFO and Composi-
portion and away from other hazardous materials. tion C-4. Crystals are characterized by mounting intact mate-
6.6.1.1 Notable IST results for explosives include ease of rial in refractive index liquids (15, 16); by recrystallizing from
ignition, deflagration, flame color, smoke color or absence, and a solvent (17, 18) or melt, that is, recrystallization occurring
sounds. when a melted compound is cooled (19-24).
E3253 − 21
FIG. 2 Scheme for Intact Low Explosive Examinations

E3253 − 21
FIG. 3 Scheme for Intact High Explosive Examinations

E3253 − 21
6.8.2 Usemicrocrystalteststoidentifyanionsandcationsof those composed of elements with relatively low atomic
oxidizers and metals (25-28). number, based on known elemental peak energies.
6.8.3 Use PLM to identify and isolate particles of interest
6.13.2 X-ray fluorescence (XRF) can be used to identify the
for other instrumental techniques (15). elemental composition of compounds, particularly those com-
posed of elements with relatively high atomic number, based
6.9 Instrumental Techniques:
upon known elemental peak energies.
6.9.1 Most of the analytical instruments found in forensic
6.13.3 X-ray diffraction (XRD) can be used to identify
laboratories lend themselves to the detection and identification
crystalline components.
of explosives and explosives-related compounds. Use the
following techniques to detect or identify explosives com-
7. Analytical Requirements for Identification
pounds and other components of explosives including, fuels,
binders, or detection agents (29).
7.1 The following sections list explosives or categories of
6.9.2 For chromatographic techniques (6.11, 6.12), compare
explosive materials and the minimum analytical requirements
the retention time (or retention factor for thin layer chroma-
for chemical identification (2, 36). Each section identifies an
tography) and mass spectra (if appropriate) to a reference
explosive or category of explosive materials, and the accept-
material analyzed under the same conditions.
able analytical technique or combination of techniques re-
6.9.2.1 Confirm chromatography detection results using an
quired to make a chemical identification.
additional separation technique with a different column or
7.2 Black Powder:
another technique, which is based on different principles and
7.2.1 The minimum requirements for identification are:
methodologies.
physical characteristics, IST (if sufficient sample), identifica-
6.9.3 Comparisontoareferencematerialisalsorequiredfor
tion of potassium nitrate (or sodium nitrate) and sulfur, and
identification when using Fourier transform infrared spectros-
characterization of charcoal (if appropriate).
copy (6.10), Raman spectroscopy (6.10), and X-ray diffraction
7.2.2 Identification of potassium nitrate (or sodium nitrate):
(6.13.3).
7.2.2.1 XRD or
6.10 Spectroscopy Identification:
7.2.2.2 FTIR or Raman and either SEM-EDS, XRF or PLM
6.10.1 Fourier transform infrared (FTIR) spectroscopy and
(using at least one of the following: optical crystallography or
Raman spectroscopy can be used to identify many organic and
microcrystal tests for anion and cation), or
inorganic explosive compounds (4, 5, 30).
7.2.2.3 Anion and cation analysis by IC and CE, or IC and
CE in combination with elemental analysis such as XRF or
6.11 Chromatography Identification:
SEM-EDS, or
6.11.1 Agas chromatograph coupled to a mass spectrometer
can be used for the identification of organic compounds (31, 7.2.2.4 PLM using a combination of optical crystallography
and microcrystal tests for the anion and cation.
32).
6.11.2 Aliquid chromatograph coupled to a mass spectrom- 7.2.2.5 Chemical spot tests can be used presumptively in
conjunction with the techniques listed above but are insuffi-
eter can be used for the identification of organic compounds
(33, 34). cient for unique identification.
6.11.3 An ion chromatograph coupled to a mass spectrom- 7.2.3 Identification of elemental sulfur:
eter can be used for the identification of ionic organic and 7.2.3.1 XRD, Raman, or GC-MS of an extract or
inorganic compounds. 7.2.3.2 PLM (optical crystallography, recrystallization) and
either SEM-EDS or XRF, or
6.12 Chromatography Detection:
7.2.3.3 SulfurchemicalspottestandeitherSEM-EDS,XRF
6.12.1 A gas chromatograph coupled to an electron capture
or PLM (optical crystallography).
(ECD), or chemiluminescence (also known as the thermal
7.2.4 Characterization of charcoal:
energy analyzer [TEA]) detector can be used for the detection
7.2.4.1 SEM-EDS (cellular structure and elemental carbon)
of organic compounds.
or PLM.
6.12.2 A liquid chromatograph coupled to an ultraviolet
7.2.4.2 The characterization of charcoal in commercial
(UV) detector or diode array detector (DAD) can be used for
black powder samples is optional.
the detection of organic compounds.
5 6
6.12.3 An ion chromatograph coupled to a conduc
...