Isotope ratio method: state-of-the-art of forensic applications to CBRNE materials

Figures & data

Figure 1. Framework for the application of isotopic signatures in forensic investigations, adapted from Ehleringer et al. [11].

Table 1. Summary of forensic applications of IRM to various chemical threats.

Application	Ratios	References
KCN and NaCN (cyanide salts) geographic origin	δ^13C δ^15N	[14, 15]
Methylphosphonic dichloride (sarin precursor) synthetic environment	δ^13C	[16]

Table 2. Summary of forensic applications of IRM to various biological threats.

Application	Ratios	References
Water source geographic origin, growth medium source, and identify co-cultured samples of spores	δ^2H δ^18O δ^13C δ^15N	[17–22]
Source seeds of Ricin	δ^15N	[23]

Table 3. Summary of forensic applications of IRM to various radiological and nuclear materials.

Application	Ratios	Reference
Unirradiated fuel materials
Uranium production date	^234U/^230Th ^235U/^231Pa ^232Th/^228Th ^226Ra/^234U ^227Ac/^235U	[24–29] [30–34]
Uranium geographic origin	^207Pb/^206Pb ^208Pb/^206Pb ^87Sr/^86Sr δ^98Mo ^143Nd/^144Nd ^34S/^32S δ^18O ^234U/^238U	[35–48]
UOC-UFx conversion detection	^238U^19F/^238U ^19F/^238U	[49, 50]
Uranium enrichment (^235U content)	^235U/U	[27, 51–56]
Uranium enrichment process	^234U/^238U ^235U/^234U	[54, 57, 58]
Irradiated fuel materials
Uranium source (mined or reprocessed)	^236U/^238U ^233U/^238U ^232U/^238U	[54, 57, 59]
Fuel burnup	various U various Pu ^100Ru/^104Ru	[60–63]
Plutonium production date	^238Pu/^234U ^239Pu/^235U ^240Pu/^236U ^242Pu/^238U ^241Pu/^241Am ^238Pu/^239Pu ^241Pu/^239Pu ^242Pu/^239Pu	[64–69]
Fuel age	^244Cm/^245Cm ^244Cm/^246Cm	[70]
Plutonium geographic origin	^18O/^16O	[66]
Reactor type	various Pu ^136Ba/^138Ba, ^137Cs/^133Cs, ^134Cs/^137Cs, ^135Cs/^137Cs, ^154Eu/^153Eu, ^150Sm/^149Sm, ^152Sm/^149Sm ^100Ru/^104Ru, ^105Pd/^110Pd	[63, 65, 71–77]
Nuclear weapon detonation detection	various Xe various I	[78, 79]
Radioactive sources and reactor components
Radioactive source age	^60Co/^60Ni ^241Am/^233Pa ^137Cs/^137Ba ^90Sr/^90Y/^90Zr	[80–84]
Graphite moderator fluence	^10B/^11B δ^7Li δ^13C ^48Ti/^49Ti ^235U/^238U ^236U/^238U ^240Pu/^239Pu ^241Pu/^239Pu ^242Pu/^239Pu δ^41Ca δ^59Ni	[59, 85–88]
Fluence of other reactor components	^10B/^11B δ^7Li δ^59Ni δ^63Ni ^49Ti/^48Ti ^114Cd/^113Cd ^158Gd/^157Gd ^94Zr/^96Zr	[59, 89–92]

Figure 2. Reactor type identification by Pu isotopic correlation, adapted from Wallenius et al. [65].

Table 4. Isotopic ratio measured in graphite moderator for fluence predictions [86].

Element	Measured ratios	Fluence range
Boron	^10B/^11B	Low
Lithium	^6Li/^7Li	Low-Intermediate
Titanium	^48Ti/^49Ti	Intermediate-High
Uranium	^235U/^238U, ^236U/^238U	Low-High
Plutonium	^240Pu/^239Pu, ^241Pu/^239Pu, ^242Pu/^239Pu	Low-High

Table 5. Description of the fractions of an explosive [108].

Explosive fraction	Purpose	Common examples
Explosive	Rapidly expand gases to destroy surrounding objects	RDX
		HMX
		PETN
		TNT
		AN
Binder	Decrease sensitivity of the explosive	SBR (styrenebutadiene)
		PIB (polyisobutylene)
Plasticizers and oils	Easier to mold and safer to handle	BEHA (bis(2-ethylhexyl) adipate)
		BEHS (bis(2-ethylhexl) sebacate)
		DIBP (diisobutyl phthalate)
		Tributyl citrate

May also contain small amounts of antioxidants, dyes, and/or taggants.

Table 6. List of explosives and their chemical names.

Common name/Abbreviation	Chemical name/Description
AN	Ammonium nitrate
BP	Black powder (mixture of potassium nitrate, sulfur, and charcoal)
ETN	Erythritol tetranitrate
HMTD	Hexamethylene triperoxide diamine
HMX	Cyclotetramethylene-tetranitramine
LX-10	HMX with 5% fluorocarbon binder “Viton”
LX-14	HMX with 5% polyurethane binder “Estane”
LX-17	TATB with 7.5% chlorofluorocarbon binder “KeL-F 800”
OCTOL	75% HMX with 25% TNT
PETN	Pentaerythritol tetranitrate
RDX	Cyclotrimethylenetrinitramine
TATB	Triamino trinitrobenzene
TATP	Triacetone triperoxide
Tetryl	2,4,6-trinitrophenyl methyl nitramine
TNT	2,4,6-Trinitrotoluene

Figure 3. Detailed framework for forensic analysis of explosives, adapted from Chesson et al. [108].

Table 7. Summary of forensic applications of IRM to various explosives threats.

Application	Ratios	References
AN geographic origin	δ^18O, δ^2H, δ^15N	[110, 111]
AN manufacturer and type	δ^13C, δ^15N, δ^18O	[112]
TATP geographic origin	δ^13C, δ^2H, δ^18O	[110, 111, 113]
PETN geographic origin	δ^13C, δ^15N	[110, 111]
RDX and HDX manufacturing process	δ^13C, δ^15N	[114]
Aromatic or nonaromatic determination	δ^13C	[8]
BP manufacturer, type, and batch	δ^13C, δ^15N, δ^18O	[112]
HMTD precursor	δ^13C, δ^15N	[115]

Ehleringer JR, Thompson AH, Podlesak DW, et al. A framework for the incorporation of isotopes and isoscapes in geospatial forensic investigations. In: West JB, et al., editors. Isoscapes: understanding movement, pattern, and process on earth through isotope mapping. Dordrecht: Springer, 2010.

 Google Scholar

Mirjankar NS, Fraga CG, Carman AJ, et al. Source attribution of cyanides using anionic impurity profiling, stable isotope ratios, trace elemental analysis and chemometrics. Anal Chem. 2016;88(3):1827–1834.

 PubMed Web of Science ®Google Scholar

Tea I, Antheaume I, Zhang BL. A test to identify cyanide origin by isotope ratio mass spectrometry for forensic investigation. Forensic Sci Int. 2012;217(1–3):168–173.

 PubMed Web of Science ®Google Scholar

Moran JJ, Fraga CG, Nims MK. Stable-carbon isotope ratios for sourcing the nerve-agent precursor methylphosphonic dichloride and its products. Talanta. 2018;186:678–683.

 PubMed Web of Science ®Google Scholar

Kreuzer HW, West JB, Ehleringer JR. Forensic applications of light-element stable isotope ratios of ricinus communis seed and ricin preparations. J Forensic Sci. 2013;58:S43–S51.

 PubMed Web of Science ®Google Scholar

Faure AL, Rodriguez C, Marie O, et al. Detection of traces of fluorine in micrometer sized uranium bearing particles using SIMS. J Anal At Spectrom. 2014;29(1):145–151.

 Web of Science ®Google Scholar

Kips R, Kristo MJ, Hutcheon ID, et al. Determination of the relative amount of fluorine in uranium oxyfluoride particles using secondary ion mass spectrometry and optical spectroscopy. Lawrence Livermore National Laboratory Report LLNL-PROC-414029. 2009; June.

 Google Scholar

Wallenius M, Mayer K, Ray I. Nuclear forensic investigations: Two case studies. Forensic Sci Int. 2006;156(1):55–62.

 PubMed Web of Science ®Google Scholar

Stebelkov V, Elantyev I, Hedberg M, et al. Determination of isotopic composition of uranium in the CMX-4 samples by SIMS. J Radioanal Nucl Chem. 2018;315(2):417–423.

 Web of Science ®Google Scholar

Tamborini G. SIMS analysis of uranium and actinides in microparticles of different origin. Microchim Acta. 2004;145(1–4):237–242.

 Web of Science ®Google Scholar

Wood HG. Effects of separation processes on minor uranium isotopes in enrichment cascades. Sci Glob Secur. 2008;16(1–2):26–36.

 Google Scholar

Fetter S. Nuclear archaeology: Verifying declarations of fissile-material production. Sci Glob Secur. 1993;3(3–4):237–259.

 Google Scholar

Christl M, Guérin N, Totland M, et al. A novel chronometry technique for dating irradiated uranium fuels using Cm isotopic ratios. J Radioanal Nucl Chem. 2019;322(3):1611–1620.

 Web of Science ®Google Scholar

Tamborini G, Wallenius M, Bildstein O, et al. Development of a SIMS method for isotopic measurements in nuclear forensic applications. Microchim Acta. 2002;139(1–4):185–188.

 Google Scholar

Palmer CJ, Gerez KR, Schwantes JM, et al. Scoping evaluation of trace isotopic ratios within the noble metal-phase as indicators of reactor class. Prog Nucl Energy. 2019;117:103059.

 Web of Science ®Google Scholar

Wallenius M, Peerani P, Koch L. Origin determination of plutonium material in nuclear forensics. J Radioanal Nucl Chem. 2000;246(2):317–321.

 Web of Science ®Google Scholar

Zhang W, Ungar K, Hoffman I, et al. Xenon isotopic signature study of the primary coolant on CANDU nuclear power plant to enhance CTBT verification. J Radioanal Nucl Chem. 2009;280(1):121–128.

 Web of Science ®Google Scholar

Kalinowski MB, Liao Y-Y, Pistner C. Discrimination of nuclear explosions against civilian sources based on atmospheric radioiodine isotopic activity ratios. Pure Appl Geophys. 2014;171(3–5):669–676.

 Web of Science ®Google Scholar

Gesh CJ. A graphite isotope ratio method primer – A method for estimating plutonium production in graphite moderated reactors. Pacific Northwest National Laboratory Report PNNL-14568; 2004.

 Google Scholar

Chesson LA, Howa JD, Lott MJ, Ehleringer JR. Development of a methodological framework for applying isotope ratio mass spectrometry to explosive components. Forensic Chem. 2016;2:9–14.

 Google Scholar

Benson SJ. Introduction of isotope ratio mass spectrometry for the forensic analysis of explosives [PhD thesis]. University of Technology Sydney. 2009.

 Google Scholar

Benson SJ, Lennard CJ, Maynard P, et al . Forensic analysis of explosives using isotope ratio mass spectrometry (IRMS)-discrimination of ammonium nitrate sources. Sci Justice. 2009;49(2):73–80.

 PubMed Web of Science ®Google Scholar

Gentile N. Exploration of the contribution of isotope ratio mass spectrometry to the investigation of explosives – A study of black powders and ammonium nitrate fertilisers [PhD thesis]. Université de Lausanne; 2014.

 Google Scholar

Howa JD, Barnette JE, Chesson LA, et al. TATP isotope ratios as influenced by worldwide acetone variation. Talanta. 2018;181:125–131.

 PubMed Web of Science ®Google Scholar

Howa JD, Lott MJ, Chesson LA, et al. Carbon and nitrogen isotope ratios of factory-produced RDX and HMX. Forensic Sci Int. 2014;240:80–87.

 PubMed Web of Science ®Google Scholar

McGuire RR, Velsko CA, Lee CG, et al. The use of post detonation analysis of stable isotope ratios to determine the type and production process of the explosive involved. Lawrence Livermore National Laboratory report UCRL-ID-113275, 1993 March.

 Google Scholar

Lock CM, Brust H, van Breukelen M, et al. Investigation of isotopic linkages between precursor materials and the improvised high explosive product hexamethylene triperoxide diamine. Anal Chem. 2012;84(11):4984–4992.

 PubMed Web of Science ®Google Scholar