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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Classification Strategies for Fusing UV/visible Absorbance and Fluorescence Microspectrophotometry Spectra from Textile Fibers
(Cambridge UP, 2018-08) Fuenffinger, Nathan; Goodpaster, John V.; Bartick, Edward G.; Morgan, Stephen L.; Chemistry and Chemical Biology, School of Science
Tracking the Progression of Triple Negative Mammary Tumors over Time by Chemometric Analysis of Urinary Volatile Organic Compounds
(Cancers, 2021-01) Woollam, Mark; Wang, Luqi; Grocki, Paul; Liu, Shengzhi; Siegel, Amanda P.; Kalra, Maitri; Goodpaster, John V.; Yokota, Hiroki; Agarwal, Mangilal
Previous studies have shown that volatile organic compounds (VOCs) are potential biomarkers of breast cancer. An unanswered question is how urinary VOCs change over time as tumors progress. To explore this, BALB/c mice were injected with 4T1.2 triple negative murine tumor cells in the tibia. This typically causes tumor progression and osteolysis in 1–2 weeks. Samples were collected prior to tumor injection and from days 2–19. Samples were analyzed by headspace solid phase microextraction coupled to gas chromatography–mass spectrometry. Univariate analysis identified VOCs that were biomarkers for breast cancer; some of these varied significantly over time and others did not. Principal component analysis was used to distinguish Cancer (all Weeks) from Control and Cancer Week 1 from Cancer Week 3 with over 90% accuracy. Forward feature selection and linear discriminant analysis identified a unique panel that could identify tumor presence with 94% accuracy and distinguish progression (Cancer Week 1 from Cancer Week 3) with 97% accuracy. Principal component regression analysis also demonstrated that a VOC panel could predict number of days since tumor injection (R2 = 0.71 and adjusted R2 = 0.63). VOC biomarkers identified by these analyses were associated with metabolic pathways relevant to breast cancer.
Studies into Exfoliation and Coating of Egyptian Blue for Application to the Detection of Latent Fingermarks
(Chem Rxiv, 2020-09-23) Shahbazi, Sorour; Goodpaster, John; Smith, Gregory; Becker, Thomas; Lewis, Simon W.
We have recently demonstrated that exfoliated Egyptian blue powder coated with cetrimonium bromide is effective for detecting latent fingermarks on a range of highly-patterned non-porous surfaces (see reference). In this extension of that work, we here present our preliminary studies into alternative approaches to preparing exfoliated Egyptian blue with a variety of different coatings. The various powders were then applied to the detection of latent fingermarks on non-porous surfaces. This proof of concept study demonstrated that there is potential improvement in performance compared to our previous work, however more comprehensive studies are required to compare the quality of the fingermarks developed with these powders against particles exfoliated in water.
Preparation, characterization, and application of a lipophilic coated exfoliated Egyptian blue for near-infrared luminescent latent fingermark detection
(Forensic Chemistry, 2020-05-01) Shahbazi, Sorour; Goodpaster, John V.; Smith, Gregory D.; Becker, Thomas; Lewis, Simon W.
A simple technique is described to create nanoscale near-infrared luminescent Egyptian blue pigment particles with lipophilic surfaces for latent fingermark detection. An exfoliated Egyptian blue powder coated with cetrimonium bromide was prepared using a simple, one-pot process. Particle size and surface coatings were characterized using scanning electron and atomic force microscopies, dynamic light scattering, and infrared and luminescence spectroscopies. This new fingermark dusting powder presents more contrast compared to uncoated Egyptian blue of comparable particle size as well as a commercial visible light fluorescent (Blitz Red) powder in the detection of aged fingermarks on model surfaces. The coated Egyptian blue pigment is a cost-effective fingermark dusting powder that reveals high contrast latent fingermarks with simple, inexpensive photography equipment.
Automated Derivatization and Identification of Controlled Substances via Total Vaporization Solid Phase Microextraction (TV-SPME) and Gas Chromatography/Mass Spectrometry (GC/MS)
(U.S. Department of Justice, Office of Justice Programs, 2018-11) Goodpaster, John V.
The hypothesis tested was that Total Vaporization - Solid Phase Microextraction (TV-SPME) will offer greater sensitivity than traditional liquid injection for controlled substances. In addition, TV-SPME was easily adapted to include either a pre-extraction or a post-extraction on-fiber derivatization step for thermally labile species. Project results were promising for all drug classes that were analyzed successfully by on-fiber derivatization as solutions. This discovery greatly improves the utility of the technique, since controlled substances are most often encountered in their solid forms in forensic science laboratories. The application of this technique to beverage samples and solid drug powders is of most interest, since these applications involve a significant decrease in sample preparation. Although not ideal for all analytes, TV-SPME with on-fiber derivatization could be a powerful technique for amine and hydroxylamine controlled substances, as well as GHB. The technique could increase analyst efficiency by reducing sample preparation time for these types of analytes. Thus, the main results of this project are a set of optimized derivatization methods that can be used in liquid injection or TV-SPfsME. This approach offers the possibility of automated sampling and derivatization for a wide variety of thermally labile compounds and the analysis of compounds that require no derivatization. Project design and methods are described. 4 figures and 1 table
Monitoring compositional changes of the lipid fraction of fingermark residues deposited on paper during storage
(Forensic Chemistry, 2016-11-01) Frick, A.A.; Chidlow, G.; Goodpaster, John V.; Lewis, S.W.; van Bronswijk, W.
Characterising the changes in fingermark composition as a function of time is of great value for improving fingermark detection capabilities by understanding the processes and circumstances under which target compounds become degraded. In this study, gas chromatography-mass spectrometry was used to monitor relative changes in the lipids from latent fingermarks over 28 days. Principal component analysis of the relative composition of 15 lipids in fingermarks showed that fingermark age was a significant contributor to the variability observed in the data, but that inter-donor variability was also significant. This was attributed principally to changes in the relative amounts of squalene, which rapidly decreased in the fingermarks. It was also observed, however, that most fingermarks exhibited relatively small changes in composition during the first seven days, followed by more rapid changes up to 28 days. Significant inter-donor variation of both initial fingermark composition and the rates and nature of loss processes was observed, which was reflected in the relative projection of samples from different donors. Finally, samples stored with no exposure to light or airflow for 28 days were projected significantly closer to the samples analysed on the day of deposition than those exposed to light, due to the reduced photodegradation rate of squalene.
Differentiation of Structurally Similar Phenethylamines via Gas Chromatography - Vacuum Ultraviolet Spectroscopy (GC – VUV)
(Elsevier, 2019-08) Roberson, Zackery R.; Goodpaster, John V.; Chemistry and Chemical Biology, School of Science
The vacuum ultraviolet region includes wavelengths shorter than 200 nm. Electronic transitions of sigma and pi bonds lie in this region, which have the potential to yield structural information. Thus, a VUV detector should be able to detect nearly any molecule analyzable by gas chromatography. This study sought to determine the extent to which structurally similar phenethylamines are differentiated using their VUV spectra. Phenethylamines are a common drug class including pseudoephedrine and illicit drugs such as methamphetamine. Several phenethylamines are difficult to analyze by electron impact mass spectrometry due to their fragmentation giving the same mass to charge ratio fragments at similar ratios. While phenethylamines are generally differentiable by retention time, an extra layer of specificity is preferred in forensic analyses. A vacuum ultraviolet (VUV) spectrophotometer coupled to a gas chromatograph was used to collect VUV spectra at high frequency between 125 and 430 nm. Eight phenethylamines were analyzed for this work using GC/VUV. A calibration curve and limit of detection study was performed that indicates a limit of detection around 10 μg mL−1 and an upper limit of linearity around 1000 μg mL−1. The spectra, analyzed by Principal Component Analysis and Discriminant Analysis, indicate the ability to reliably differentiate each of the drugs from one another including structural isomers and diastereomers. Lastly, five “street” samples containing amphetamines were analyzed to demonstrate “real world” performance.
Preparation and characterization of micro-bore wall-coated open-tubular capillaries with low phase ratios for fast-gas chromatography–mass spectrometry: Application to ignitable liquids and fire debris
(Elsevier, 2019) Roberson, Zackery R.; Goodpaster, John V.; Chemistry and Chemical Biology, School of Science
Fast Gas Chromatography (GC) allows for analysis times that are a fraction of those seen in traditional capillary GC. Key modifications in fast GC include using narrow, highly efficient columns that can resolve mixtures using a shorter column length. Hence, a typical fast GC column has an inner diameter of 100–180 μm. However, to maintain phase ratios that are consistent with typical GC columns, the film thickness of fast GC stationary phases are also low (e.g., 0.1–0.18 μm). Unfortunately, decreased film thickness leads to columns with very low sample capacity and asymmetric peaks for analytes that are not sufficiently dilute. This paper describes micro-bore (50 μm i.d.) capillary columns with thick films (1.25 μm), and low phase ratios (10). These columns have greater sample capacity yet also achieve minimum plate heights as low as 110 μm. Hence, separation efficiency is much higher than would be obtained using standard GC columns. The capillary columns were prepared in-house using a simple static-coating procedure and their plate counts were determined under isothermal conditions. The columns were then evaluated using temperature programming for fast GC–MS analysis of ignitable liquids and their residues on fire debris exemplars. Temperature ramps of up to 75 °C min−1 could be used and separations of ignitable liquids such as gasoline, E85 fuel, and lighter fluid (a medium petroleum distillate) were complete within 3 min. Lastly, simulated fire debris consisting of ignitable liquids burned on carpeting were extracted using passive headspace absorption-elution and the residues successfully classified.
Fabrication of a Self-Assembled and Flexible SERS Nanosensor for Explosive Detection at Parts-Per-Quadrillion Levels from Fingerprints
(RSC, 2018-05) Liyanage, Thakshila; Rael, Ashur; Shaffer, Sidney; Zaidi, Shozaf; Goodpaster, John V.; Sardar, Rajesh; Chemistry and Chemical Biology, School of Science
Apart from high sensitivity and selectivity of surface-enhanced Raman scattering (SERS)-based trace explosive detection, efficient sampling of explosive residue from real world surfaces is very important for homeland security applications. Herein, we demonstrate an entirely new SERS nanosensor fabrication approach. The SERS nanosensor was prepared by self-assembling chemically synthesized gold triangular nanoprisms (Au TNPs), which we show display strong electromagnetic field enhancements at the sharp tips and edges, onto a pressure-sensitive flexible adhesive film. Our SERS nanosensor provides excellent SERS activity (enhancement factor = ∼6.0 × 106) and limit of detection (as low as 56 parts-per-quadrillions) with high selectivity by chemometric analyses among three commonly military high explosives (TNT, RDX, and PETN). Furthermore, the SERS nanosensors present excellent reproducibility (<4.0% relative standard deviation at 1.0 μM concentration) and unprecedentedly high stability with a “shelf life” of at least 5 months. Finally, TNT and PETN were analyzed and quantified by transferring solid explosive residues from fingerprints left on solid surfaces to the SERS nanosensor. Taken together, the demonstrated sensitivity, selectivity, and reliability of the measurements as well as with the excellent shelf life of our SERS nanosensors obviate the need for complicated sample processing steps required for other analytical techniques, and thus these nanosensors have tremendous potential not only in the field of measurement science but also for homeland security applications to combat acts of terror and military threats.
Interlaboratory evaluations of the performance of elemental analytical methods for the forensic analysis and comparisons of electrical tapes
(Elsevier, 2019-03) Martinez-Lopez, Claudia; Trejos, Tatiana; Coulson, Sally; Goodpaster, John; Igowsky, Katherine; Kuczelinis, Felix; Mehltretter, Andria; Pollock, Edward; Simmross, Ulrich; Weimer, Robyn; Weis, Peter; Almirall, Jose R.; Chemistry and Chemical Biology, School of Science
Adhesive tapes are an important type of evidence related to violent crimes such as the construction of improvised explosive devices and kidnappings as well as involved in other types of common evidence such as drug packaging. The methods of comparison of tape evidence consist of physical and microscopic examination followed by chemical analysis of the organic and inorganic components inherent to the tapes as part of their formulations. This work evaluates the performance of the conventional methods used in forensic analysis of adhesive tapes (physical and microscopic examination, FTIR, Py-GC-MS, and SEM-EDS) and the more recently developed elemental methods, LIBS and LA-ICP-MS, for the comparison of tape samples in different laboratories. Two interlaboratory exercises were designed to study the performance of the different analytical methods for the forensic analysis of electrical tapes. The exercises were developed with the objective to imitate forensic case scenarios where known and question tapes are compared following the laboratory’s analytical protocol. The participants were asked to compare the tape samples as in a regular forensic case. Seven (7) laboratories participated in the two interlaboratory exercises. All the laboratories performing SEM-EDS in both interlaboratory exercises (#1 and #2) were able to correctly associate the pairs of tapes originating from the same rolls, therefore the rate of false negatives was zero. Two of the laboratories performing SEM-EDS for the first interlaboratory exercise incorrectly associated two pairs of tapes belonging to different rolls, resulting in a 17% false positive rate. One of the laboratories performing SEM-EDS for interlaboratory exercise #2 incorrectly associated two pairs of tapes belonging to different rolls, resulting in a 13% false positive rate. Up to 7 and 8 elements were detected by SEM-EDS for interlaboratory exercise #1 and #2, respectively. The increased sensitivity and selectivity of LIBS and LA-ICP-MS methods allowed to distinguish all the pairs of tapes originating from different sources and for correctly associate the tapes originating from the same rolls, resulting in no false positives or false negatives. In addition, increased characterization of the samples was obtained by detecting up to 14 elements by LIBS and 27 elements by LA-ICP-MS for interlaboratory exercise #1, and 17 elements by LIBS and 32 elements by LA-ICP-MS for interlaboratory exercise #2. A match criterion of ±5 s allowed to numerically compare LIBS ratios and LA-ICP-MS signal areas for a more objective assessment of the differences between the tape samples.

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