John Goodpaster

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https://hdl.handle.net/1805/6679

Evaluation of the Odor Compounds Sensed by Explosive-Detecting Canines

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. Dr. Goodpaster's research examines 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.

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Rapid and Accurate Determination of Stern-Volmer Quenching Constants
(1999) Goodpaster, John V.; McGuffin, Victoria L
In this work, a novel system has been designed, characterized, and validated for the determination of fluorescence quenching constants. Capillary flow injection methods are used to automate the preparation and mixing of the fluorophore and quencher solutions. Because of the small diameter of the capillary (75-200 mu m), fluorescence measurements can be made without corrections for primary and secondary absorbance effects. The fluorescence spectrometer is equipped with a charge-coupled device (CCD) that has a detection limit of 3.0 X 10-9 M (2.3 ppb) and a linear dynamic range of 10 5 for integration times of 0.01-10 s. This spectrometer has a 300 nm spectral range with 1 nm resolution, allowing the fluorescence quenching constants to be calculated at single wavelengths or over integrated wavelength ranges. This system was validated by comparison to traditional methods for the determination of Stern-Volmer constants for alternant and nonalternant polycyclic aromatic hydrocarbons with nitromethane and triethylamine.
Characterization of Automotive Paint Clear Coats by Ultraviolet Absorption Microspectrophotometry with Subsequent Chemometric Analysis
(2010-10) Liszewski, Elisa A; Lewis, Simon W; Siegel, Jay A; Goodpaster, John V.
Clear coats have been a staple in automobile paints for almost thirty years and are of forensic interest when comparing transferred and native paints. However, the ultraviolet (UV) absorbers in these paint layers are not typically characterized using UV microspectrophotometry, nor are the results studied using multivariate statistical methods. In this study, measurements were carried out by UV microspectrophotometry on 71 samples from American and Australian automobiles, with subsequent chemometric analysis of the absorbance spectra. Sample preparation proved to be vital in obtaining accurate absorbance spectra and a method involving peeling the clear coat layer and not using a mounting medium was preferred. Agglomerative hierarchical clustering indicated three main groups of spectra, corresponding to spectra with one, two, and three maxima. Principal components analysis confirmed this clustering and the factor loadings indicated that a substantial proportion of the variance in the data set originated from specific spectral regions (230–265 nm, 275–285 nm, and 300–370 nm). The three classes were well differentiated using discriminant analysis, where the cross-validation accuracy was 91.6% and the external validation accuracy was 81.1%. However, results showed no correlation between the make, model, and year of the automobiles.
Quantitative Analysis of Humectants in Tobacco Products Using Gas Chromatography (GC) with Simultaneous Mass Spectrometry (MSD) and Flame Ionization Detection (FID)
(2013-06) Rainey, Christina L; Shifflett, John R; Goodpaster, John V.; Bezabeh, Dawit Z
This paper describes the modification of an existing gas chromatographic (GC) method to incorporate simultaneous mass spectrometric (MSD) and flame ionization detection (FID) into the analysis of tobacco humectants. Glycerol, propylene glycol, and triethylene glycol were analyzed in tobacco labeled as roll-your-own (RYO), cigar, cigarette, moist snuff, and hookah tobacco. Tobacco was extracted in methanol containing 1,3-butanediol (internal standard), filtered, and separated on a 15 m megabore DB-Wax column. Post-column flow was distributed using a microfluidic splitter between the MSD and FID for simultaneous detection. The limits of detection for the FID detector were 0.5 μg/mL (propylene glycol and triethylene glycol) and 0.25 μg/mL (glycerol) with a linear range of 2–2000 μg/mL (propylene glycol and triethylene glycol) and 1–4000 μg/mL (glycerol). The limits of detection for the MSD detector were 2 μg/mL (propylene glycol and triethylene glycol) and 4 μg/mL (glycerol) with a linear range of 20–2000 μg/mL (propylene glycol and triethylene glycol) and 40–4000 μg/mL (glycerol). Significant improvement in the sensitivity of the MSD can be achieved by employing selective ion monitoring (SIM) detection mode. Although a high degree of correlation was observed between the results from FID and MSD analyses, marginal chromatographic resolution between glycerol and triethylene glycol limits the applicability of FID to samples containing low levels of both of these humectants. Utilizing MSD greatly improves the reliability of quantitative results because compensation for inadequate chromatographic resolution can be accomplished with mass selectivity in detection.
Solvent Azeotropes in Art Conservation
(Office of the Vice Chancellor for Research, 2014-04-11) Carrison, Megan; Goodpaster, John V.; Smith, Gregory Dale
Solvent mixtures are often fine-tuned by art conservators for the difficult tasks of safely removing yellowed varnishes and obfuscating dirt from oil paintings. These two goals are often loosely termed “picture cleaning.” Concern has been raised over the impact of differential evaporation rates for solvents in the cleaning mixture. Differential evaporation can lead to changes in the mixture’s potency over time and potentially lead to solvent mixtures on the surface of the artwork having solubility characteristics deleterious to artists’ oil paints. Azeotropic mixtures of solvents have been proposed as an alternative for maintaining consistent solvent composition. Azeotropes are specific mixtures of two or more solvents that behave as a single solvent and maintain a constant composition at their boiling point. The azeotropes that have appeared in the art conservation literature are taken from tables of azeotropic compositions in the CRC Handbook given at their boiling point. This research examines whether these solvent blends, in particular a hexane/isopropanol combination found to be an effective cleaner in the treatment of painted royal sleighs at the Palace of Versailles, in fact behave azeotropically under room temperature evaporation conditions. For the first time, the actual evaporation behavior of this purported azeotropic mixture will be explored in depth. A range of hexane/isopropanol mixtures around the boiling point azeotrope composition have been assessed for their room temperature vapor pressure and evaporation weight loss kinetics. Aliquots of the evaporating solutions are also being analyzed chemically using gas chromatography of both the liquid phase and the vapor phase in the headspace. This research aims to provide conservators information on the evaporation of purportedly azeotropic solvent blends and to suggest new approaches to the cleaning of oil paintings.
Microbial Degradation of Gasoline in Soil: Effect of Season of Sampling
(Elsevier, 2015-06) Turner, Dee A.; Pichtel, J.; Rodenas, Y.; McKillip, John L.; Goodpaster, John V.; Department of Chemistry & Chemical Biology, IU School of Science
In cases where fire debris contains soil, microorganisms can rapidly and irreversibly alter the chemical composition of any ignitable liquid residue that may be present. In this study, differences in microbial degradation due to the season in which the sample is collected was examined. Soil samples were collected from the same site during Fall, Winter, Spring and Summer and the degradation of gasoline was monitored over 30 days. Predominant viable bacterial populations enumerated using real-time PCR and reverse transcriptase polymerase chain reaction (RT-PCR) enumeration revealed the predominant viable bacterial genera to be Alcaligenes, Bacillus, and Flavobacterium. Overall, the compounds most vulnerable to microbial degradation are the n-alkanes, followed by the mono-substituted alkylbenzenes (e.g., toluene, ethylbenzene, propylbenzene and isopropylbenzene). Benzaldehyde (a degradation product of toluene) was also identified as a marker for the extent of biodegradation. Ultimately, it was determined that soil collected during an unusually hot and dry summer exhibited the least degradation with little to no change in gasoline for up to 4 days, readily detectable n-alkanes for up to 7 days and relatively high levels of resilient compounds such as o-xylene, p-xylene and 1,3,5-trimethylbenzene. These results demonstrate, however, that prompt preservation and/or analysis of soil evidence is required in order to properly classify an ignitable liquid residue.
Mapping explosive residues on galvanized pipe bomb fragments using total vaporization solid phase microextraction (TV-SPME)
(Royal Society of Chemistry, 2015-12) Bors, Dana; Goodpaster, John V.; Department of Chemistry and Chemical Biology, School of Science
Solid phase microextraction (SPME) is a popular sampling technique whereby analytes are sorbed to a coated fiber and subsequently desorbed into an analytical instrument. In headspace SPME, analytes partition between the sample, the headspace above the sample, and the SPME fiber coating. In total vaporization SPME (TV-SPME), sample extracts are heated until both the solvent and analytes completely vaporize, whereupon the analytes partition between the vapor phase and the SPME fiber. In this study, TV-SPME using a polyethylene glycol fiber was coupled with fast gas chromatography/mass spectrometry to identify components of double-base smokeless powder (DBSP). Nitroglycerin (NG), diphenylamine (DPA) and ethyl centralite (EC) were separated in under 5 min. For NG, the optimal sample volume (70 μL), extraction temperature (60 °C) and extraction time (20 min) resulted in a method that was over twelve fold more sensitive than traditional liquid injection and with a detection limit below 1 ppb. This method was then used to quantify DBSP residue on post-blast debris from five galvanized steel pipe bombs. The mean concentration of NG on the fragments was 0.25 ppm (w/w). An average of 1.01 mg of NG was recovered from the devices. Finally, the distribution of NG could be “mapped” by tracking the original locations of each fragment within the device. These maps showed that the distribution of NG was far from uniform. In fact, the concentration of the NG on fragments originating from the end caps was several fold higher than in other locations. This finding can help guide the selection of bomb fragments for chemical analyses in real-world scenarios.
Detection of prohibited treatment products on racing tires using headspace solid phase microextraction (SPME) and gas chromatography/ mass spectrometry (GC/MS)
(Royal Society of Chemistry, 2016-01) Kranz, William D.; Carroll, Clinton J.; Goodpaster, John V.; Department of Chemistry & Chemical Biology, School of Science
A variety of commercial tire treatments are available that purport to help automobile tires better cling to the surface of a road or racetrack, raising concerns in the professional racing community that such products might be used to illicitly boost performance in competitive events. These tire treatments are reputed to cut lap times and improve handling and maneuverability. In some cases, the manufacturers even boast that their products are “undetectable” (i.e., impervious to the scrutiny of laboratory testing). In this study, a number of banned tire treatment products were evaluated principally by gas chromatography-mass spectrometry (GC-MS) using solid phase microextraction (SPME) as a pre-concentration technique. The chemicals off-gassed by each product were determined and grouped into two broad categories: ‘plasticizer-based’ tire treatment products and ‘hydrocarbon-based’ tire treatment products. This information was then applied to the analysis of genuine tire samples provided by the United States Auto Club (USAC), a professional racing association. Over the course of one year, 10 out of the 71 questioned samples tested positive for a prohibited treatment product. The manufacturers' claims regarding their products' invisibility to lab tests were largely proven to be unfounded: both the products themselves and the tires treated with them can be identified by a number of characteristic volatile compounds. These included known plasticizers such as pentanedioic acid diethyl ester, plasticizer-related compounds such as 2-ethyl-1-hexanol, and dearomatized distillates.
Odor Compounds Detected by Explosive-Detecting Canines
(Office of the Vice Chancellor for Research, 2010-04-09) Goodpaster, John V.; Lotspeich, Erica; Roemer, Neoshia; Cummins, Josh
I will exhibit, together with several students, a research project sponsored by the Department of Defense. Venture funds were used for undergraduate student salaries and travel. We will demonstrate laboratory studies that determined the amount of vapor that is generated by an explosive and, hence, the amount of odor that is available to an explosives-detecting canine. The students will be available to explain the experiments as well as the results of a live test of several trained canines.
Endothelial disruptive proinflammatory effects of nicotine and e-cigarette vapor exposures
(American Physiological Society, 2015-07-15) Schweitzer, Kelly S.; Chen, Steven X.; Law, Sarah; Van Demark, Mary; Poirier, Christophe; Justice, Matthew J.; Hubbard, Walter C.; Kim, Elena S.; Lai, Xianyin; Wang, Mu; Kranz, William D.; Carroll, Clinton J.; Ray, Bruce D.; Bittman, Robert; Goodpaster, John V.; Petrache, Irina; Department of Biochemistry & Molecular Biology, IU School of Medicine
The increased use of inhaled nicotine via e-cigarettes has unknown risks to lung health. Having previously shown that cigarette smoke (CS) extract disrupts the lung microvasculature barrier function by endothelial cell activation and cytoskeletal rearrangement, we investigated the contribution of nicotine in CS or e-cigarettes (e-Cig) to lung endothelial injury. Primary lung microvascular endothelial cells were exposed to nicotine, e-Cig solution, or condensed e-Cig vapor (1-20 mM nicotine) or to nicotine-free CS extract or e-Cig solutions. Compared with nicotine-containing extract, nicotine free-CS extract (10-20%) caused significantly less endothelial permeability as measured with electric cell-substrate impedance sensing. Nicotine exposures triggered dose-dependent loss of endothelial barrier in cultured cell monolayers and rapidly increased lung inflammation and oxidative stress in mice. The endothelial barrier disruptive effects were associated with increased intracellular ceramides, p38 MAPK activation, and myosin light chain (MLC) phosphorylation, and was critically mediated by Rho-activated kinase via inhibition of MLC-phosphatase unit MYPT1. Although nicotine at sufficient concentrations to cause endothelial barrier loss did not trigger cell necrosis, it markedly inhibited cell proliferation. Augmentation of sphingosine-1-phosphate (S1P) signaling via S1P1 improved both endothelial cell proliferation and barrier function during nicotine exposures. Nicotine-independent effects of e-Cig solutions were noted, which may be attributable to acrolein, detected along with propylene glycol, glycerol, and nicotine by NMR, mass spectrometry, and gas chromatography, in both e-Cig solutions and vapor. These results suggest that soluble components of e-Cig, including nicotine, cause dose-dependent loss of lung endothelial barrier function, which is associated with oxidative stress and brisk inflammation.
Mapping smokeless powder residue on PVC pipe bomb fragments using total vaporization solid phase microextraction
(Elsevier, 2017-07) Bors, Dana; Goodpaster, John V.; Department of Chemistry & Chemical Biology, School of Science
Quantitating post-blast explosive residue is not a common practice in crime labs as it is typically not legally relevant. There is value in quantitation, however, if the distribution of residues on Improvised Explosive Devices (IEDs) can help guide future sample collection and/or method development. Total vaporization solid phase microextraction gas chromatography mass spectrometry (TV-SPME/GC/MS) was used to quantify residues of double-base smokeless powder (DBSP), which includes nitroglycerin (NG), diphenylamine (DPA), and ethyl centralite (EC) on post-blast PVC pipe bomb fragments. The analytical method could separate the three constituents in under 5 min with a detection limit under 1 ppb, which demonstrates high throughput while maintaining high sensitivity. The method was optimized for nitroglycerin, as it is the most indicative of DBSP. The average mass of nitroglycerin recovered from an entire PVC device was 1.0 mg. The average mass of diphenylamine recovered was much lower (24 μg) and only one device had detectable levels of EC. The typical concentration of NG on any given fragment was approximately 15–30 ppm (μg NG/g fragment). However, there was no correlation between the mass of a fragment and the mass of residue upon it. Instead, the residue was distributed such that the highest concentration of residues was found on end cap fragments.

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