[PDF] A Survey On The Interpretive Gc Ms Analysis Of Fire Debris eBook

Author : Anthony Thomas Parks
Publisher :
Page : 43 pages
File Size : 23,43 MB
Release : 2018
Category : Chemistry
ISBN : 9780438372801

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The practice of arson analysis in a forensic science laboratory is based upon detecting the presence of ignitable liquids. If an ignitable liquid is present, it is suggestive of arson; if no ignitable liquid is found an arson claim is more difficult to assert. Ignitable liquids are detected using gas chromatography coupled with mass spectrometry. Instrumental results from a GC/MS can display components of an ignitable liquid but an analyst needs to make the final decision. Even with correct instrumentation and suggested guidelines, ignitable liquid analysis can be subjective and based upon the analysts' education and experience. To better understand the interpretive practices of the fire debris analysis community, a survey consisting of reference samples, mixture standards, and multiple unknowns was created in consultation with the Los Angeles Police Department Arson Unit. The samples consisted of different substrates with varying classes and volumes of ignitable liquid. They were created using a destructive distillation method first developed by the State of Florida Bureau of Forensic Fire and Explosives Analysis. Extraction of the samples was completed using a carbon strip to perform passive headspace absorption following the ASTM E 1412 method. The samples were analyzed with a GC/MS following National Commission on Forensic Science parameters. To maintain confidentiality, participant responses are stripped of identifiers and the results of the survey, details about the procedure, and discussions will be presented.

Author : Eric Stauffer
Publisher : Academic Press
Page : 683 pages
File Size : 39,75 MB
Release : 2007-12-10
Category : Law
ISBN : 0080556264

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The study of fire debris analysis is vital to the function of all fire investigations, and, as such, Fire Debris Analysis is an essential resource for fire investigators. The present methods of analysis include the use of gas chromatography and gas chromatography-mass spectrometry, techniques which are well established and used by crime laboratories throughout the world. However, despite their universality, this is the first comprehensive resource that addresses their application to fire debris analysis. Fire Debris Analysis covers topics such as the physics and chemistry of fire and liquid fuels, the interpretation of data obtained from fire debris, and the future of the subject. Its cutting-edge material and experienced author team distinguishes this book as a quality reference that should be on the shelves of all crime laboratories. Serves as a comprehensive guide to the science of fire debris analysis Presents both basic and advanced concepts in an easily readable, logical sequence Includes a full-color insert with figures that illustrate key concepts discussed in the text

Author : Kelly M. McHugh
Publisher :
Page : 106 pages
File Size : 23,99 MB
Release : 2010
Category : Fire investigation
ISBN :

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Current fire debris analysis procedure involves using the chromatographic patterns of total ion chromatograms, extracted ion chromatograms, and target compound analysis to identify an ignitable liquid according to the American Society for Testing and Materials (ASTM) E 1618 standard method. Classifying the ignitable liquid is accomplished by a visual comparison of chromatographic data obtained from any extracted ignitable liquid residue in the debris to the chromatograms of ignitable liquids in a database, i.e. by visual pattern recognition. Pattern recognition proves time consuming and introduces potential for human error. One particularly difficult aspect of fire debris analysis is recognizing an ignitable liquid residue when the intensity of its chromatographic pattern is extremely low or masked by pyrolysis products. In this research, a unique approach to fire debris analysis was applied by utilizing the samples' total ion spectrum (TIS) to identify an ignitable liquid, if present. The TIS, created by summing the intensity of each ion across all elution times in a gas chromatography-mass spectrometry (GC-MS) dataset retains sufficient information content for the identification of complex mixtures . Computer assisted spectral comparison was then performed on the samples' TIS by target factor analysis (TFA). This approach allowed rapid automated searching against a library of ignitable liquid summed ion spectra. Receiver operating characteristic (ROC) curves measured how well TFA identified ignitable liquids in the database that were of the same ASTM classification as the ignitable liquid in fire debris samples, as depicted in their corresponding area under the ROC curve. This study incorporated statistical analysis to aid in classification of an ignitable liquid, therefore alleviating interpretive error inherent in visual pattern recognition. This method could allow an analyst to declare an ignitable liquid present when utilization of visual pattern recognition alone is not sufficient.

Author : Betty-Jane De Vos
Publisher :
Page : pages
File Size : 50,85 MB
Release : 2013
Category :
ISBN :

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Gas chromatography - mass spectrometry (GC-MS) is an established instrumental technique used for the analysis of fire debris for accelerant detection. However, matrix problems, such as pyrolysis product interference, are still encountered. These interferences often lead to inconclusive interpretation of the chromatographic results. This study describes methods for analysing arson accelerants using gas chromatography coupled with ion trap mass spectrometry. The latter technique lends itself to both conventional (GC-MS) as well as tandem mass spectrometry (GC-MS-MS). Since petrol (gasoline) is one of the more common distillate blends used by arsonists, especially in South Africa, the identification of petrol in fire debris samples was investigated. In order to overcome pyrolysis product interference and improve detection selectivity of the aromatic hydrocarbons in petrol residues, tandem mass spectrometry was used in combination with capillary gas chromatography. The added parameter of the third dimension of selectivity proved to be superior to conventional GC-MS in obtaining characteristic aromatic hydrocarbon profiles for petrol without interference from pyrolysis artefacts.

Author : Kenyon Evans-Nguyen
Publisher : Springer Nature
Page : 356 pages
File Size : 47,56 MB
Release : 2019-10-08
Category : Science
ISBN : 3030258343

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This text provides training on the fundamental tools and methodologies used in active forensic laboratories for the complicated analysis of fire debris and explosives evidence. It is intended to serve as a gateway for students and transitioning forensic science or chemistry professionals. The book is divided between the two disciplines of fire debris and explosives, with a final pair of chapters devoted to the interplay between the two disciplines and with other disciplines, such as DNA and fingerprint analysis. It brings together a multi-national group of technical experts, ranging from academic researchers to active practitioners, including members of some of the premier forensic agencies of the world. Readers will gain knowledge of practical methods of analysis and will develop a strong foundation for laboratory work in forensic chemistry. End-of-chapter questions based on relevant topics and real-world data provide a realistic arena for learners to test newly-acquired techniques.

Author : Jose R. Almirall
Publisher : CRC Press
Page : 276 pages
File Size : 19,76 MB
Release : 2004-02-11
Category : Law
ISBN : 0203492722

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Ongoing advances in arson detection tools and techniques increase the importance of scientific evidence in related court proceedings. In order to assemble an airtight case, investigators and forensic scientists need a resource that assists them in properly conducting the chemical analysis and interpretation of physical evidence found at scenes of s