Positive Identification of the Principal Component of a White Powder as Scopolamine by Quantitative One-Dimensional and Two-Dimensional NMR Techniques

• NCJ Number: 222161
• Journal: Journal of Forensic Sciences Volume: 53 Issue: 1 Dated: January 2008 Pages: 151-161
• Author(s): Terry J. Henderson Ph.D.; David B. Cullinan Ph.D.; Richard J. Lawrence M.A.; Jonathan M. Oyler B.A.
• Date Published: January 2008
• Length: 11 pages
• Publication Format: Article
• Publication Type: Test/Measurement
• Language: English
• Country: United States of America

Annotation

This paper presents the procedures and results of a complete structural determination of a white powder submitted for chemical weapons screening after it was seized in an intelligence investigation.

Abstract

Several nuclear magnetic resonance (NMR) techniques were able to provide a good estimate of the specific types and number of various atoms that composed the principal component of the powder and essentially all of the information necessary to determine its chemical structure, positively identifying the principal component as the scopolamine biotoxin. A small fraction of the powder dissolved in D2O was subjected to a series of one-dimensional and two-dimensional techniques that were used to characterize the molecular structure of the powder's major component and positively identify it. Quantitative one-dimensional experiments identified individual proton and carbon atom sites. Conventional 14N spectroscopy detected a single nitrogen atom site. Heteronuclear single quantum coherence data correlated all protons to their directly bonded carbon atom, and, together with the quantitative spectra, were used to determine the number of protons directly bonded to each carbon atom. The presence of a methyl, carboxyl, and a benzyl group was also identified from these data. Correlation spectroscopy detected a three-proton and a nine-proton JH,H network, representing a CH2CH moiety and seven carbon atom rings, respectively. These five elements were assembled into a nearly complete molecular structure by using long-range, J-coupled, 1H-13C pairs detected by heteronuclear multiple bond correlation spectroscopy and 1H-1H dipolar-coupled pairs found from nuclear Overhauser effect spectroscopy data. Only a single oxygen atom site could not be inferred from NMR data, but its presence was inferred from comparisons to target analyte structures to complete the structure of the scopolamine molecule. Procedures for confirming these results are described. 6 figures, 2 tables, and 50 references