Association of Fired Cartridge Residues to Unburned Smokeless Powders Using GC-MS and Multivariate Statistical Procedures

Association of Fired Cartridge Residues to Unburned Smokeless Powders Using GC-MS and Multivariate Statistical Procedures
Author: Rebecca L. Boyea
Publisher:
Total Pages: 146
Release: 2020
Genre: Electronic dissertations
ISBN:

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Forensic analysis of smokeless powders has historically focused on the analysis of unburned powder or gunshot residue. The analysis of fired cartridge residues and subsequent statistical association to the corresponding unburned powder has only recently been investigated. Previous work in our laboratory employed liquid chromatography-time of flight-mass spectrometry (LC-TOFMS) and chemometric procedures to investigate association of fired cartridge residues to the corresponding unburned powders.2 While successful association was achieved for some powders, LC-TOFMS is not readily available in forensic laboratories. A widely available alternative is gas chromatography-mass spectrometry (GC-MS). The work presented here demonstrates the use of GC MS for the analysis of unburned powder and fired cartridge residues, followed principal components analysis (PCA) and hierarchical cluster analysis (HCA) to investigate association and differentiation of fired cartridge residues to the corresponding unburned powder. Both PCA and HCA resulted in distinct groupings of the unburned powders, based largely on the abundance of ethyl centralite and dibutyl phthalate. Despite variability and decreased abundances observed in all fired cartridge residues, successful association of the fired cartridges to the corresponding unburned powder was possible but was limited by the original composition of the unburned powder. Overall, this work demonstrates that GC-MS and chemometric procedures are effective tools for the association of fired cartridge residues and unburned powders.

Analysis and Characterization of Smokeless Powders and Smokeless Powder Residues

Analysis and Characterization of Smokeless Powders and Smokeless Powder Residues
Author: Emily Christine Lennert
Publisher:
Total Pages: 0
Release: 2022
Genre:
ISBN:

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The ability to associate a smokeless powder, smokeless powder residue, or organic gunshot residue (OGSR) to one another may be helpful in determining the origin of a suspected sample and aid in linking a suspect to a crime scene. In this study, smokeless powders were extracted and analyzed via gas chromatography -- mass spectrometry (GC-MS) and direct analysis in real time -- high resolution mass spectrometry (DART-HRMS). Subsequently, group definition was performed using hierarchical cluster analysis and principal component analysis followed by internally validated classification models. Then, smokeless powder residues were generated in-lab and extracted. Resulting residue data from each instrument was classified within the respective smokeless powder model using linear discriminant analysis (LDA) with external test sets. Residue groupings and classification models were also generated. Ammunition was loaded with known smokeless powder, then fired to collect OGSR from cloth targets. The OGSR was extracted and analyzed via DART-HRMS and GC-MS, then tested against the smokeless powder and residue models to determine the association of OGSR to its intact smokeless powder as well as to lab generated residues. Reference classes for the OGSR samples in the LDA prediction were determined via flow charts for informed analyst determination of class in smokeless powder and residue models. Standards of common smokeless powder components were pyrolyzed and an expected pyrolysis products profile was created for each sample based on the intact composition. Similarity and correlation metrics including Pearson’s correlation, Sørensen-Dice similarity coefficient, and Concordance correlation were evaluated in the comparison of smokeless powder to residue and residue to expected pyrolysis products. Pearson’s correlation was used in the comparison of smokeless powder to OGSR and smokeless powder residue to OGSR.

Modern Methods and Applications in Analysis of Explosives

Modern Methods and Applications in Analysis of Explosives
Author: Jehuda Yinon
Publisher: John Wiley & Sons
Total Pages: 320
Release: 1996-08-06
Genre: Science
ISBN: 9780471965626

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An up-to-date handbook, with the latest advances including all the various methods and techniques for analyzing explosives. Explosive compounds and mixtures, residues--their recovery and clean-up procedures--chromatography, polarography, spectroscopy, environmental analysis and mass spectroscopy are among the topics covered.

Analysis of the Homogeneity of Powders by Gas Chromatography-mass Spectrometry

Analysis of the Homogeneity of Powders by Gas Chromatography-mass Spectrometry
Author: Michaela M. Harper
Publisher:
Total Pages: 14
Release: 2017
Genre: Chemistry
ISBN: 9781369724059

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In forensic drug chemistry, most street drugs are formulated by the combination of powders, one or more of which is an illicit drug. Because the amount of controlled substances contained in the mixture determines sentencing, laboratory practices must ensure that portions combined for analysis are representative of the entire seizure. Often it is difficult to ascertain whether or not the mixture is truly uniform, especially when all powders combined are white. The analyst may rely on visual cues that have not been evaluated. In this study, caffeine and mannitol were chosen as surrogates for illicit drug and cutting agent. Caffeine and mannitol were chosen for this project due to their accessibility as a non-controlled substance and abundance in real world forensic exhibits. Mixtures of caffeine and mannitol were combined at several different known purities and then analyzed via gas chromatography-mass spectrometry (GC-MS). Experiments were conducted to evaluate the homogeneity of mixtures prepared by changing time mixed, amount mixed and color of substance.

Feasibility of Gunshot Residue Detection Via Its Organic Constituents. Part I

Feasibility of Gunshot Residue Detection Via Its Organic Constituents. Part I
Author: MH. Mach
Publisher:
Total Pages: 13
Release: 1978
Genre: Gas chromatography
ISBN:

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A quick, convenient, and reliable test for detecting gunshot residue is needed to cope with the increasing number of crimes involving handguns. Chemical color tests for nitrates [1] and for antimony, barium, and lead [2] have been used, but these methods lack the required sensitivity and specificity for forensic purposes. Two instrumental techniques, neutron activation analysis and atomic absorption, have found some acceptance by crime laboratories. Neutron activation analysis has been used to detect antimony and barium in hand samples [3], but it suffers from the drawbacks that samples must be sent out for analysis and that it is insensitive to lead. Atomic absorption has been used to detect lead by flame atomization [4], and antimony and barium have been detected with a flameless atomizer [5]. This approach has extended the availability of gunshot residue analysis. However, the costs still limit the number of laboratories with the required equipment. Perhaps a more serious limitation of any technique that is based on the bulk amounts of antimony, barium, or lead on a person's hands is the possibility of environmental or occupational sources of these elements on the hands. This limitation requires setting a threshold often higher than the amount deposited by firing. Furthermore, the amount of residue on the hand declines very rapidly with time.

The Analysis of Explosives

The Analysis of Explosives
Author: Jehuda Yinon
Publisher: Elsevier
Total Pages: 323
Release: 2013-10-22
Genre: Technology & Engineering
ISBN: 1483140059

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The Analysis of Explosives surveys the principles of the various analytical methods, describes how these methods are used for the analysis of explosives, and reviews the major analytical work carried out in this field. Organized into 15 chapters, this book begins with the classification of explosives. Subsequent chapters discuss the different methods for the analysis of explosives. The detection and identification of explosive residues and hidden explosives are also explained. This monograph will be useful as a reference book for chemists in analytical and forensic laboratories, as well as a textbook for graduate students in analytical chemistry and forensic sciences.