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The Jackson Group
Department of Forensic and Investigative Science

Research

Outline

Our long-term goal is to catalyze the progress of biomedical, analytical and forensic research through the development of mass spectrometric instrumentation. More specifically, we develop fast chromatographic methods, new ion sources and new ways of performing tandem mass spectrometry. Once the capabilities of the new devices and methods are understood, controlled and optimized, selected applications are sought to demonstrate the benefits of the new instrumentation to the broader scientific community. Click on the projects below to learn more. 
  1. new ways of fragmenting gas-phase bio-ions, including peptides and oligosaccharides, in tandem mass spectrometers using kiloelectronvolt helium ions. We use the term charge transfer dissociation (CTD-MS) to describe the mechanism of activation.  (example publication) 
  2. new forensic applications of isotope ratio mass spectrometry, including hair, nails and blow flies. (example publication) 
  3. understanding the mass spectrometric fragmentation behavior of novel psychoactive substances (NPSs).  (example publication) 
  4. development of new algorithms for mass spectral comparisons
  5. experimental and theoretical approaches to understand the evaporation of ignitable liquids at elevated temperatures (e.g. 200 °C).  (example publication)  
Click on the publications tab in the menu bar to  see all our recent publications .
Jackson group at ASMS, San Diego, 2018  

Research Projects


1) CHARGE TRANSFER DISSOCIATION (CTD) FOR BIOLOGICAL MASS SPECTROMETRY

We have successfully developed new instruments for the fragmentation of gas-phase biological ions, including metastable atom-activated dissociation (MAD) and charge transfer dissociation (CTD). CTD relies on the exothermic transfer of a charge from a helium cation to a biological gas-phase cation, with subsequent fragmentation of the newly-oxidized biological ion. The unique manner of energy transfer makes CTD is currently applied to oligosaccharides, where CTD efficiencies up to 40% are possible. 
Students: Mario Mendis, Zach Sasiene, Halle Edwards, Mayara Matos.
Funding source: NIH 1R01GM114494-01 (PI Stephen Valentine, WVU) & NSF CHE 1710376 (2018-2020) Zach with CTD Bruker ion trap, 2018

2) NEW FORENSIC APPLICATIONS FOR ISOTOPE RATIO MASS SPECTROMETRY (IRMS)

Compound specific isotope analysis (CSIA) can provide unique insights into the sources of materials of forensic interest. For example, CSIA can be used to trace the origins of cocaine to within specific growing regions in South America, or to determine the common sources of high explosives. We use our limited-edition LC-IRMS to determine CSIA values of amino acids in proteinaceous materials like hair, human tissues,  decomposing animals, blow flies (see picture below) and oysters. We are currently using the instrument to establish investigative leads from human hair. 
Students: Halle Edwards
Funding source: DOJ NIJ 2013-DN-BX-K007 (2013-2016)
Hair Doesn't lie image Blow fly larvae having a feast in the Jackson lab!

3&4) STRUCTURAL CHARACTERIZATION OF EMERGING SYNTHETIC DRUGS & A NEW MASS SPECTRAL COMPARATOR

This project is lead by Tyler Davidson and was funded by NIJ in September 2018. The project, which is a collaboration with Profs. Randall Clark and Jack DeRuiter at Auburn University, will help practitioners understand the mass spectra of existing and emerging novel psychoactive substances. In addition to studying fragmentation behavior of synthetic drugs, the project will also develop a new mass spectral comparison algorithm to assist with compound identifications.
Example publication.
Students: Tyler Davidson, Sam Mehnert, Alia Hacker, Alex Adeoye
Funding source: DOJ NIJ 2018-75-CX-033 (2019-2020)
Tyler performing data analysis ESI Spectrum of 34MDPV

5) MATHEMATICAL MODEL FOR THE EVAPORATION (WEATHERING) OF GASOLINE

This project was also funded by NIJ in September 2018. The project, which is a collaboration with Profs. Ruth Smith and Victoria McGuffin at Michigan State University, will help practitioners understand the detailed chemical relationships between fresh gasoline and the weathered residues found in fire debris. We are developing a mathematical model to explain the differences in evaporation rates for different components at different temperatures. Unlike previous studies, our model can predict more precisely the composition of residues at elevated temperatures (e.g. >200 °C).  Example publication.
Students: Caitlyn Lear, Ahna Kotula, Evan Ferweda
Funding source: DOJ NIJ 2018-DU-BX-0225 (2019-2020)
Dr. Fan rinsing weathered gasoline residues
Gasoline weathering figure

Mario and Mayara in Lab