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John Goodpaster Ph.D.
Director of Forensic Sciences Program, Assistant Professor, Chemistry
B.A., Chemistry, Gustavus Adolphus College, 1995
M.S., Criminal Justice, Michigan State University, 2000
Ph.D., Chemistry, Michigan State University, 2000
My group’s research interests lie within the area of forensic analytical chemistry, which combines the powerful methods of analytical chemistry with the acute social relevance of forensic science. In particular, projects related to the analysis and detection of ignitable liquids, explosives and trace evidence are clearly focused on law enforcement and defense-related applications. Although instrumentation is critical for our work, we also make generous use of applied multivariate statistical analysis. These techniques are universally applicable to a number of data types (e.g., spectra, chromatograms and elemental data) and enable us to visualize patterns and relationships that would otherwise be difficult or even impossible to discern.
- Biodegradation of Ignitable Liquids: The identification of ignitable liquid residues in fire debris is a key finding for determining the cause and origin of a suspicious fire. However, the complex mixtures of organic compounds that comprise ignitable liquids are susceptible to microbiological attack following collection of the sample. Biodegradation can result in selective removal of many of the compounds required for identification of an ignitable liquid. Such degradation has been found to occur rapidly in substrates such as soil, rotting wood, or other organic matter. Furthermore, fire debris evidence must often be stored for extended periods at room temperature prior to analysis due to case backlogs and available evidence storage. Hence, extensive damage to ignitable liquid residues by microbes poses a significant threat to subsequent laboratory work. In this research, the effects of microbial degradation of numerous ignitable liquids in soil have been monitored as a function of time. Key findings include the loss of n-alkanes, which showed the most dramatic decrease in gasoline as well as petroleum distillates, while branched alkanes remained unchanged. Mono-substituted benzenes also showed the most dramatic loss in gasoline. These findings have been confirmed in practical samples gathered after a test of incendiary devices by the Indianapolis Fire Department (see photo below).
- Instrumental Analysis of Explosives: While black powder has been in use for hundreds of years, its commercial availability is declining. As a result, black powder substitutes (propellant formulations with reduced or no sulfur content) are more commonly encountered as explosive fillers in improvised explosive devices (IEDs) (see photo micrograph below). Protocols for the analysis of post-blast residues generally rely upon an appropriate solvent extraction, chromatographic separation and detection by a suitably sensitive and specific technique such as mass spectrometry. However, many explosives present difficulties for separation and/or detection due to low retention in liquid chromatography or thermal instability in gas chromatography-mass spectrometry (GC-MS). Two long standing examples are Pyrodex and Triple Seven, which contain potassium perchlorate, potassium nitrate and the organic fuels benzoic acid, nitrobenzoic acid and dicyandiamide (DCDA). My group has accomplished the analysis of these materials using GC-MS through derivatization techniques and conclusive identification via mass spectrometry. In addition, this research project included validation steps using actual post-blast debris. Based upon the efforts of two undergraduate chemistry students, a GC/MS method has been successfully developed to detect benzoic acid, nitrobenzoic acid and dicyandiamide (DCDA) in Pyrodex and Triple Seven.
- Improvised Explosive Devices: The goals of this project are to evaluate the fragmentation of common pipe bombs, with a particular focus on the effects of container material and explosive fill (see photo below). In collaboration with the Indiana State Police, several devices have been constructed from 1-inch nominal diameter galvanized steel, black steel and PVC pipe with various low explosive fillers such as Pyrodex and double-base smokeless powder (DBSP). All devices were suspended in open air and initiated with electric matches. Container fragments were gathered and examined for morphology, mass distribution and explosive residue. The mass distribution of the container fragments was evaluated and high speed video footage of the pipe bomb explosions was also captured. We have analyzed this footage to reveal where the pipe containers first failed as well as provided estimates for the velocity of expelled fragments. The distribution of fragment masses for all devices was approximately exponential. However, PVC pipes generated larger numbers of smaller fragments. The high-speed video footage of the pipe bomb explosions also shows a clear difference between devices consisting of PVC pipe versus steel pipe. Devices made from PVC pipe first ruptured along the pipe nipple itself, regardless of explosive filler. Devices made from steel pipe first ruptured at the end caps. Overall, the highest estimated fragment velocities originated from devices using galvanized steel/DBSP (351 mph – 476 mph) and black steel/DBSP (291 mph – 556 mph).
- Canine Detection of Explosives: The remote detection of explosives generally relies upon detecting volatile compounds that are emitted by the explosive itself. Detection of these compounds can be achieved through instrumentation or by specially trained canines. While instruments are designed and built to respond to particular chemical species, it is not always clear what chemical species generates a canine alert. In addition, canines have the ability to “generalize” and correctly alert to explosive formulations that are similar, but not identical, to those with which they have trained. This would tend to indicate that there are common chemical odors for some types of explosives. A long-term project in our laboratory is examining the effect of odor availability and differing odor compounds on canine detection. As the chemical composition of the headspace above explosive formulations is more completely understood, it should be possible to test the extent to which canine alerts correlate to the compounds of interest. Furthermore, the ability of canine training aids to reliably deliver appropriate odors to the canine can be evaluated, particularly in the case of the more volatile and chemically unstable species such as organic peroxide explosives.
- Chemometric Analysis of Trace Evidence: Forensic scientists often rely upon the class characteristics of a questioned item (Q) to assess whether it may share a common source with a known sample (K). In order to accomplish this, a set of discriminating analytical techniques must be available to evaluate these characteristics and assign a type to both the Q and K. If the two samples are both associated to a given type, the frequency of occurrence for the evidence type in question should be estimated and thereby the significance of the association discerned. Traditionally, class evidence has been studied qualitatively and classification of samples was achieved through visual inspection. However, the use of computerized pattern recognition can significantly improve the reproducibility, differentiation and reliability of the data thus obtained. In particular, we have made extensive use of techniques such as agglomerative hierarchical clustering (AHC), principal components analysis (PCA) and discriminant analysis (DA) to examine data such as elemental composition, infrared spectra, gas chromatograms, and UV-visible absorbance spectra. Materials of interest include electrical tape, automotive clear coats, dyed cotton fibers (see photo below), hair dyes, and pigmented inks. Currently, we are using multivariate analysis to demonstrated the extent to which subtle yet reliable differences exist between samples as well as what aspects of the data best capture these differences.
- Health Effects and Biomarkers of Tobacco Use: This represents a new research direction and collaboration with the IU Dental School. We were approached by a member of the Tobacco Cessation and Biobehavioral Center with a request to assist in the analysis of a family of new tobacco products that are being test marketed in Indiana and work is underway. Collaborative studies on the partitioning of tobacco components into biofilms, oral tissue and hair are planned. We am interested from a forensic standpoint in what could be termed “lifestyle markers” that could be found in human hair. These are compounds that reflect the consumption of alcohol, drugs or tobacco by a subject. This would complement earlier work in the analysis of human hair surface lipids.
D. A. Turner and J. V. Goodpaster “The Effect of Microbial Degradation on the Chromatographic Profiles of Tiki Torch Fuel, Lamp Oil, and Turpentine” J. Forensic Sci. (In Press).
D. A. Turner and J. V. Goodpaster “Comparing the Effects of Weathering and Microbial Degradation on Gasoline Using Principal Components Analysis” J. Forensic Sci. (In Press).
B. J. Routon, B. B. Kocher and J. V. Goodpaster “Discriminating Hodgdon Pyrodex and Triple Seven Using Gas Chromatography-Mass Spectrometry” J. Forensic Sci, 2011, 56, 194-199.
J. A. Barrett, J. A. Siegel and J. V. Goodpaster “Forensic Discrimination of Dyed Hair Color: II. Multi-variate Statistical Analysis” J. Forensic Sci. 2011, 56, 95-101.
C. L. Rainey, P. A. Conder and J. V. Goodpaster “Chemical Characterization of Dissolvable Tobacco Products Promoted To Reduce Harm” Journal of Agricultural and Food Chemistry 2011, 59, 2745-2751.
R. Hibbard, J. V. Goodpaster and M. R. Evans “Factors Affecting the Forensic Examination of Automotive Lubricating Oils” J. Forensic Sci. 2011, 56, 741-753.
E. A. Liszewski, S. Lewis, J. A. Siegel and J. V. Goodpaster "Characterization of Automotive Paint Clear Coats by Ultraviolet Absorption Microspectrophotometry with Subsequent Chemometric Analysis” Appl. Spectroscopy 2010, 64, 1122-1125.
J. A. Barrett, J. A. Siegel and J. V. Goodpaster “Forensic Discrimination of Dyed Hair Color: I. UV-Visible Microspectrophotometry” J. Forensic Sci. 2010, 55, 323-333.
J. V. Goodpaster and E. A. Liszewski “Forensic Analysis of Dyed Textile Fibers” Anal. Bioanal. Chem. 2009, 394, 2009-2018.
D. A. Turner and J. V. Goodpaster “Effects of Microbial Degradation on Ignitable Liquids in Soil” Anal. Bioanal. Chem. 2009, 394, 363-371.