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Title: Stable Carbon and Nitrogen Isotope Ratios of Sodium and Potassium Cyanide as a Forensic Signature

Abstract

Sodium and potassium cyanide are highly toxic, produced in large amounts by the chemical industry, and linked to numerous high-profile crimes. The U.S. Centers for Disease Control and Prevention has identified cyanide as one of the most probable agents to be used in a future chemical terrorism event. We investigated whether stable C and N isotopic content of sodium and potassium cyanide could serve as a forensic signature for sample matching, using a collection of 65 cyanide samples. A few of these samples displayed non-homogeneous isotopic content associated with degradation to a carbonate salt and loss of hydrogen cyanide. Most samples had highly reproducible isotope content. Of these, >95% could be properly matched based on C and N isotope ratios, with a false match rate <3%. These results suggest that stable C and N isotope ratios are a useful forensic signature for matching cyanide samples.

Authors:
 [1];  [2];  [1];  [2];  [1];  [1]
  1. Pacific Northwest National Laboratory (PNNL)
  2. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
Work for Others (WFO)
OSTI Identifier:
1033144
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Forensic Sciences; Journal Volume: 57; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CARBON; CARBONATES; CHEMICAL INDUSTRY; CHEMICAL WARFARE AGENTS; CYANIDES; DETECTION; DISEASES; HYDROCYANIC ACID; ISOTOPE RATIO; NITROGEN ISOTOPES; POTASSIUM; SABOTAGE; SODIUM; forensic science; potassium cyanide; sodium cyanide; isotope ratio mass spectrometry; sample matching

Citation Formats

Kruzer, Helen W, Horita, Juske, Moran, James J, Tomkins, Bruce A, Janszen, Derek B, and Carman, April. Stable Carbon and Nitrogen Isotope Ratios of Sodium and Potassium Cyanide as a Forensic Signature. United States: N. p., 2012. Web. doi:10.1111/j.1556-4029.2011.01946.x.
Kruzer, Helen W, Horita, Juske, Moran, James J, Tomkins, Bruce A, Janszen, Derek B, & Carman, April. Stable Carbon and Nitrogen Isotope Ratios of Sodium and Potassium Cyanide as a Forensic Signature. United States. doi:10.1111/j.1556-4029.2011.01946.x.
Kruzer, Helen W, Horita, Juske, Moran, James J, Tomkins, Bruce A, Janszen, Derek B, and Carman, April. Sun . "Stable Carbon and Nitrogen Isotope Ratios of Sodium and Potassium Cyanide as a Forensic Signature". United States. doi:10.1111/j.1556-4029.2011.01946.x.
@article{osti_1033144,
title = {Stable Carbon and Nitrogen Isotope Ratios of Sodium and Potassium Cyanide as a Forensic Signature},
author = {Kruzer, Helen W and Horita, Juske and Moran, James J and Tomkins, Bruce A and Janszen, Derek B and Carman, April},
abstractNote = {Sodium and potassium cyanide are highly toxic, produced in large amounts by the chemical industry, and linked to numerous high-profile crimes. The U.S. Centers for Disease Control and Prevention has identified cyanide as one of the most probable agents to be used in a future chemical terrorism event. We investigated whether stable C and N isotopic content of sodium and potassium cyanide could serve as a forensic signature for sample matching, using a collection of 65 cyanide samples. A few of these samples displayed non-homogeneous isotopic content associated with degradation to a carbonate salt and loss of hydrogen cyanide. Most samples had highly reproducible isotope content. Of these, >95% could be properly matched based on C and N isotope ratios, with a false match rate <3%. These results suggest that stable C and N isotope ratios are a useful forensic signature for matching cyanide samples.},
doi = {10.1111/j.1556-4029.2011.01946.x},
journal = {Journal of Forensic Sciences},
number = 1,
volume = 57,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2012},
month = {Sun Jan 01 00:00:00 EST 2012}
}
  • Sodium and potassium cyanide are highly toxic, produced in large amounts by the chemical industry, and linked to numerous high-profile crimes. The U.S. Centers for Disease Control and Prevention has identified cyanide as one of the most probable agents to be used in a future chemical terrorism event. We investigated whether stable C and N isotopic content of sodium and potassium cyanide could serve as a forensic signature for sample matching, using a collection of 65 cyanide samples. A few of these samples displayed non-homogeneous isotopic content associated with degradation to a carbonate salt and loss of hydrogen cyanide. Mostmore » samples had highly reproducible isotope content. Of these, >95% could be properly matched based on C and N isotope ratios, with a false match rate <3%. These results suggest that stable C and N isotope ratios are a useful forensic signature for matching cyanide samples.« less
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  • Potassium cyanide, a known poison, was used a model compound to determine the feasibility of using anionic impurities as a forensic signature for matching KCN samples back to their source. In this study, portions of eight KCN stocks originating from four countries were separately dissolved in water and analyzed by high performance ion chromatography (HPIC) using an anion exchange column and conductivity detection. Sixty KCN aqueous samples were produced from the eight stocks and analyzed for 11anionic impurities. Hierarchal cluster analysis and principal component analysis were used to demonstrate that KCN samples cluster according to source based on the concentrationsmore » of their anionic impurities. The F-ratio method and degree-of-class separation (DCS) were used for feature selection on a training set of KCN samples in order to optimize sample clustering. The optimal subset of anions needed for sample classification was determined to be sulfate, oxalate, phosphate, and an unknown anion named unk5. Using K-nearest neighbors (KNN) and the optimal subset of anions, KCN test samples from different KCN stocks were correctly determined to be manufactured in the United States. In addition, KCN samples from stocks manufactured in Belgium, Germany, and the Czech Republic were all correctly matched back to their original stocks because each stock had a unique anionic impurity profile. The application of the F-ratio method and DCS for feature selection improved the accuracy and confidence of sample classification by KNN.« less
  • Amounts of dry NO{sub 3}-N deposition and N isotope ratios in wet and dry NO{sub 3}-N deposition have been simultaneously determined by examining differences between precipitation collected by open funnels and throughfall collected beneath an artificial Christmas tree. Samples were collected in a forest clearing on Walker Branch Watershed, near Oak Ridge, Tennessee. From mid-summer to early autumn, NO{sub 3}-N fluxes beneath the artificial tree were always greater than those measured in precipitation indicating the tree's effectiveness as a passive collector of dry NO{sub 3}-N deposition. Dry NO{sub 3}-N deposition averaged 60 {+-} 9% of total (wet and dry) deposition.more » The mean ({+-} SD) calculated {delta}{sup 15}N value for NO{sub 3}-N in dry deposition was + 5.6 {+-} 2.1{per_thousand} (n = 6 sampling periods ranging from 4 to 15 days). On average, this was {approx} 6{per_thousand} heavier than measured {delta}{sup 15}N values for NO{sub 3}-N in precipitation. The calculated {delta}{sup 15}N value for NO{sub 3}-N in dry deposition was consistent with that expected if NO{sub x} precursors to HNO{sub 3} vapor (the major constituent of dry deposition at this site) originated principally from coal combustion.« less