ASTM E2998-16

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:E2998 −16 An American National Standard
Standard Practice for
Characterization and Classification of Smokeless Powder
This standard is issued under the fixed designation E2998; 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 and health practices and determine the applica-
bility of regulatory limitations prior to use.
1.1 This practice describes procedures for characterization
and analysis of smokeless powders recovered from explosives
2 2. Referenced Documents
incidents (1, 2), materials or objects containing gunshot
residue (3) when visible grains are present, or bulk samples of 2.1 ASTM Standards:
powder. E620 Practice for Reporting Opinions of Scientific or Tech-
nical Experts
1.2 Smokeless powder is characterized by shape, color,
E1492 Practice for Receiving, Documenting, Storing, and
texture, manufacturing toolmarks, markers, dimensional
Retrieving Evidence in a Forensic Science Laboratory
measurements, and chemical composition (4-6).
E1618 TestMethodforIgnitableLiquidResiduesinExtracts
1.3 Smokeless powder is an energetic material classified as
from Fire Debris Samples by Gas Chromatography-Mass
a low explosive or propellant. Smokeless powder can be
Spectrometry
further classified as single-base, double-base, or triple-base.
3. Terminology
1.4 Analysis of post-blast debris and items containing gun-
shot residue when visible grains of smokeless powder are not
3.1 Definitions of Terms Specific to This Standard:
present is beyond the scope of this practice.
3.1.1 ball powders, n—a class of smokeless powders pro-
1.5 This practice will provide guidelines for the analysis of duced by a process where the final grain morphologies are
spherical, flattened-ball, or flake.
organic components of smokeless powders using various
instrumental techniques, such as gas chromatography-mass
3.1.2 double-base, n—propellant containing nitrocellulose
spectrometry, liquid chromatography, and Fourier transform
and nitroglycerin.
infrared spectroscopy.
3.1.3 deterrent, n—a compound to slow the burning rate of
1.6 The values stated in SI units are to be regarded as
a powder.
standard. No other units of measurement are included in this
3.1.4 energetic, n—an explosive compound used to enhance
standard.
the burning rate of a powder.
1.7 This standard involves handling of low explosives and
3.1.5 extruded powders, n—a class of smokeless powders
potentially other energetic materials. It is strongly suggested
produced by an extrusion process where the final grain
that an analyst be trained in the storage and safe handling of
morphologies are disc or cylinder.
energetic materials and be familiar with the properties and
3.1.6 grain, n—an individual particle of smokeless powder.
hazards of explosives.
3.1.7 marker, n—a colored grain of smokeless powder to
1.8 This standard cannot replace knowledge, skill, or ability
assist in the visual identification of a bulk reloading smokeless
acquired through appropriate education, training, and experi-
powder.
ence and should be used in conjunction with sound profes-
sional judgment.
3.1.8 perforation, n—aholeinadiscpowderoroneormore
1.9 This standard does not purport to address all of the
holes running through the length of a cylinder powder created
safety concerns, if any, associated with its use. It is the
during the manufacturing process in extruded powders.
responsibility of the user of this standard to establish appro-
3.1.9 single-base, n—propellant containing nitrocellulose as
the major energetic material.
This practice 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 Oct. 1, 2016. Published October 2016. DOI: 10.1520/ For referenced ASTM standards, visit the ASTM website, www.astm.org, or
E2998-16. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
The boldface numbers in parentheses refer to a list of references at the end of Standards volume information, refer to the standard’s Document Summary page on
this standard. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2998−16
3.1.10 smokeless powder, n—apropellantandlowexplosive 6. Apparatus
composed of nitrocellulose and other organic and inorganic
6.1 Stereo light microscopewithanappropriatelightsource.
compounds.
6.2 Magnifying lamp with at least 3 diopter magnification.
3.1.11 stabilizer, n—a compound to prevent or slow down
6.3 Gas chromatograph-mass spectrometer—A gas chro-
self-decomposition.
matograph (GC) capable of using capillary columns and being
3.1.12 triple-base, n—propellant containing nitrocellulose,
interfaced to a mass spectrometer (MS) operating in electron
nitroglycerin, and nitroguanidine.
ionization (EI) mode.
6.4 Fourier transform infrared spectrometer (FTIR)—An
4. Summary of Practice
FTIR capable of acquiring spectra in the mid-infrared region.
4.1 The physical properties of smokeless powder grains are
6.4.1 Micro-FTIR.
recorded by visual examination using a stereo light
6.5 GCwithflameionizationdetector(FID),thermalenergy
microscope, micrometer, manual measuring device, digital
analyzer (TEA), or electron capture detector (ECD).
measurement and recording device, or camera.
6.6 Capillary electrophoresis (CE) system.
4.2 The significant physical properties of smokeless pow-
6.7 Liquid chromatograph (LC).
ders to measure are diameter, length, and thickness. The
significant physical properties to record are shape, color,
6.8 LC-MS.
perforations, texture, striations (manufacturing toolmarks), and
6.9 Digital imaging system and computer.
markers.
6.10 Digital camera that can attach to or be used in
4.3 Techniques are described for the extraction of organic
conjunction with a stereo light microscope.
components of smokeless powders for instrumental analysis.
7. Chemicals, Reagents, and Reference Materials
4.4 The chemical properties and composition of smokeless
powders can be determined by a combination of techniques
7.1 Purity of Reagents—Reagent grade or better chemicals
which may include burn testing, gas chromatography, liquid
should be used in all tests. Unless otherwise indicated, it is
chromatography, capillary electrophoresis, mass spectrometry,
intended that all reagents conform to the specifications of the
and Fourier transform infrared spectroscopy (7-12).
Committee on Analytical Reagents of the American Chemical
Society where such specifications are available. Other grades
5. Significance and Use
may be used, provided it is first ascertained that the reagent is
of sufficiently high purity to permit its use without lessening
5.1 This practice establishes guidelines for the characteriza-
the accuracy of the determination.
tion of smokeless powder which can be used as an explosive
for improvised explosive devices or as a propellant, such as for
7.2 Solvents—Methylene chloride and acetone (ACS re-
small arms ammunition and for military ordnance.
agent grade or better) or other appropriate solvents of equal
quality are acceptable.
5.2 Thispracticeestablishestheminimumcriterianecessary
to classify smokeless powders.
7.3 Test Mixture—The test mixture should consist of
nitroglycerin, diphenylamine, ethyl centralite, and 2,6-
5.3 The morphology of smokeless powder is a distinct
dinitrotoluene. The final test solution is prepared by diluting
characteristic used for classification and identification pur-
the above mixture such that the concentration of each compo-
poses.
nent is no greater than 0.005 % weight/volume (0.05 mg/mL)
5.4 The identification of a questioned sample as smokeless
in the chosen solvent (see 7.2). Additional compounds com-
powder (that is, it is a propellant or low explosive) does not
monlyfoundinsmokelesspowdersmayalsobeincludedinthe
require the identification of chemical components of a smoke-
test mixture, such as methyl centralite, 2,4-dinitrotoluene,
less powder other than nitrocellulose.
2-nitrodiphenylamine, 4-nitrodiphenylamine, diethylphthalate,
and dibutylphthalate.
5.5 Identification of organic compounds associated with
7.3.1 Appropriate concentrations of individual reference
smokeless powders is a requirement to classify a smokeless
materials or standards of these compounds may be used in
powder sample as single-base, double-base, or triple-base.
addition to or instead of a test mixture.
5.6 Additional analytical techniques may be available that
NOTE 1—In addition to component identification, appropriate concen-
are not mentioned within this document that are acceptable for
trations of the test mixture (or standards) can be used to evaluate overall
the characterization and analysis of smokeless powders.
instrument performance or sensitivity (for example, column resolution,
instrument detection limits).
5.7 The requirements to associate a questioned smokeless
powder to a unique smokeless powder product by brand name
or intercomparison of two or more questioned powders are
Reagent Chemicals, American Chemical Society Specifications, American
beyond the scope of this document (13-15).
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
5.8 The identification of smokeless powder residue in the
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
absence of whole or partial grains is beyond the scope of this
and National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,
document. MD.
E2998−16
7.4 Internal Standard—An appropriate internal standard 8.9 When two or more smokeless powders are obviously
(for example, undecane, decane) may be used in the extraction present, separate them into similar morphological groups and
solvent for GC and LC analyses. examine separately if necessary.
7.5 Reference Smokeless Powders—Reference smokeless
9. Analysis Plan for the Characterization of Smokeless
powders can be obtained as bulk reloading powders from
Powders
commercial and retail sources or directly from the distributor
or manufacturer.
9.1 Characterization of a smokeless powder involves iden-
7.5.1 Reference smokeless powders may be analyzed as
tifying the unique physical characteristics of the powder along
positive controls or comparison samples following the same
with chemical analysis (4-6) to identify the nitrocellulose
procedure for questioned samples. (whichiscommontoallsmokelesspowders)andotherorganic
components present in propellants.
7.6 GC Carrier Gas—Helium or hydrogen of purity 99.995
% or higher.
9.2 Analysis Plan Summary:
9.2.1 Visual examination and recording of physical charac-
7.7 Deionized Water—18 megohms or better.
teristics
7.8 Polystyrene Film Standard.
9.2.2 Extractions and analysis of organic components
7.9 FTIR Supplies—Salt plates, mortar and pestle, pellet
9.2.3 Burn test (if sufficient sample is available)
press.
9.3 Visual Examination and Recording of Physical Charac-
7.10 Glassware and Other Supplies—Disposable test tubes,
teristics:
pipettes, beakers, autosampler vials, weigh boats, weigh paper,
9.3.1 Use a stereo light microscope if necessary to observe
watch glasses.
and record the shape, color, markers, perforations, toolmarks,
irregular shapes, and any unique physical characteristics.
8. Sample Handling
9.3.1.1 If feasible, capture a scaled image of the powder for
comparison to similar known powders.
8.1 Observe the appropriate procedures for handling and
documentation of all submitted samples as described in Prac- 9.3.2 Record the shape (morphology) of the powder grain:
tice E1492. 9.3.2.1 Disc—a flat circular grain (coins), either solid or
containing a perforation, of varying thickness typically under
8.2 Open and examine the item in order to determine that it
0.35 mm.
is consistent with its description.
9.3.2.2 Cylinder (or rod)—a short rod-like grain either solid
8.3 If the item is suspected of containing residues of an
or containing one or more perforations.
ignitable liquid, perform an ignitable liquid extraction and
NOTE 2—Most cylinder powders used in small arms ammunition have
analysis on the item (or sample of bulk powder) prior to
a single perforation which is often difficult to observe because of the
continuing with the analysis for smokeless powder. Refer to
graphite coating on the grains or from effects caused by the mechanical
Test Method E1618.
cutting of the grain. Large cylindrical powders having multiple perfora-
8.3.1 Warning—Headspace extraction techniques for ignit-
tions are characteristic of military propellants.
able liquids should be performed at temperatures below 40°C
9.3.2.3 Sphere (or ball)—aroundgrainwithnoflatsurfaces.
on specimens.
9.3.2.4 Flattened-ball—asphericalgrainthatisflattenedtop
8.4 On a clean surface, conduct a visual examination of the
and bottom (some extremely flattened) and may exhibit radial
item.
stress fractures.
8.4.1 An examination lamp with an optical magnifier or a
9.3.2.5 Flake—a flat irregularly shaped grain usually with a
stereolightmicroscopecanbeusedtoenhancethedetectionof
rough non-uniform surface.
small-grain powders.
9.3.2.6 Agglomerate—multiple small spherical grains ad-
hering together (such as grapes on a vine).
8.5 Photograph observed grains in situ on debris samples (if
9.3.2.7 Lamel—a thin square or parallelogram grain (made
possible and probative).
from a sheet manufacturing process).
8.6 Physically remove a representative sample of suspected
9.3.2.8 Irregular—a highly modified grain lacking any par-
smokeless powder from debris samples and transfer to a
ticular shape with no consistently measurable dimension such
suitable sample holder.
as length or diameter.
8.7 For bulk powders, a representative sample should be
9.3.3 Coarse dimensional measurements of the diameter,
separated from bulk powders for analysis as a safety consid-
length, or width of powder grains in the specimen can be
eration. Store the remaining bulk powders per laboratory
determined through a side by side comparison to reference
policy and local regulations.
smokeless powders of similar morphology or by use of
measurement tools.
8.8 Separate smokeless powder grains from any other ma-
terials in the sample, using a stereo light microscope if 9.3.3.1 Precise measurement of diameter, length, or thick-
ness is not required for class identification of smokeless
necessary.
8.8.1 Other energetic materials, such as black powder and powders.
flash powder, are sometimes combined with smokeless powder 9.3.4 A specimen containing powder of one or more differ-
in explosives casework. ent types of morphology may be further differentiated and
E2998−16
treated as separate specimens based on differing physical 9.4.2.3 After extracting the specimen, transfer an aliquot of
characteristics noted in the microscopical analysis. the extract into an appropriate vial for analysis. An analysis
sequence should include solvent blanks, reference materials,
9.3.4.1 Further differentiation is not required for class iden-
controls, and standards as necessary.
tification of smokeless powder but may be useful for future
intercomparison between two or more powders or associating
NOTE 4—Specimens may be diluted as necessary depending on the
a questioned powder with a manufacturer or by brand name.
sensitivity of the instrumental technique(s) used for analysis.
9.4 Extraction and Analysis of Organic Compounds:
9.4.2.4 For specimens containing no nitroglycerin, analyze
9.4.1 A solvent extraction is followed by an instrumental
the extracted grains by FTIR to detect nitrocellulose.
technique or combination of techniques that is capable of
9.4.2.5 For samples containing nitroglycerin, the alternate
identifying nitroglycerin and other organic compounds present
extraction and analysis scheme (see 9.4.3) should be used to
in smokeless powders.
remove nitroglycerin from the powder prior to analysis for
9.4.1.1 Two different solvent extraction schemes using
nitrocelluloseasspectralsimilaritiesarenotedbetweenthetwo
methylene chloride or acetone are described in this section for components.
the initial extraction or solvation of smokeless powders. An
9.4.3 Alternate Solvent Extraction and Analysis Scheme for
analyst may choose to use either or both extraction schemes as
Organic Compounds:
necessary depending upon the desired results.
9.4.3.1 Acetone is used in this extraction and analysis
9.4.1.2 Other solvents, such as methanol or chloroform, are
scheme for the purpose of dissolving powder grains to increase
suitable for the extraction of smokeless powders but are not
the efficiency of extraction of organic compounds from the
covered by this practice.The solubility of nitrocellulose versus
nitrocellulose. This extraction scheme may also be used to
theotherorganicadditivesinasolventisanimportantfactorin
extract nitroglycerin from double- and triple-base powders to
choosing a suitable extraction solvent.
enable FTIR analysis of the nitrocellulose. If the powder
9.4.1.3 GC-MS and LC-MS are acceptable techniques to
specimen was previously extracted using another solvent,
identify nitroglycerin and other organic compounds (4, 7-9). remove any remaining solvent prior to beginning this extrac-
tion scheme.
9.4.1.4 FTIR is an acceptable technique to identify nitro-
glycerin and other organic compounds unless significant 9.4.3.2 Add approximately 500 µL of acetone to a test tube
amounts of co-extractable compounds are present in which containing up to 10 mg of powder. Allow the acetone to
case an additional orthogonal technique (such as those listed in completely dissolve the grains which will take approximately
9.4.1.5) may be necessary.
60 minutes with occasional agitation or vortex mixing. Once
dissolved, allow the acetone to evaporate to dryness.Astream
9.4.1.5 A combination of two or more orthogonal
of purified air or an inert gas can be used to accelerate
techniques, such as GC-ECD, GC-FID, GC-TEA, CE, and LC
evaporation without heat.
analysis, are acceptable to identify nitroglycerin and other
organic compounds (11, 12).
NOTE 5—Some of the organic components have low boiling points and
9.4.1.6 Warning—Methylene chloride may not be an ap-
could be lost if heat is applied during evaporation.
proved or optimal solvent for some instrumental techniques. If
9.4.3.3 Extract the dried residue with up to 500 µL of
indicated,followthestepsin9.4.3usinganappropriatesolvent
methylene chloride for up to 15 minutes with occasional
for analysis.
agitation. Transfer the methylene chloride extract to a second
9.4.1.7 Thenitroglycerinindouble-andtriple-basepowders
test tube. Repeat these steps two additional times, transferring
should be removed through solvent extraction prior to ana
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