Registration is not required, simply click the link below at the time of the meeting.
Poster presentations will occur during the social hour (5:30 – 6:30 PM) and oral presentations will follow the business meeting (typically 7:00 – 8:00 PM).
Oral Presentation Abstracts
Starting the Year on a High Note: Application of Direct Analysis in Real Time – High-resolution Mass Spectrometry to the Analysis of Complex Cannabis Matrices
Megan I. Chambers
In recent years, the application of direct analysis in real time – high-resolution mass spectrometry (DART-HRMS) to forensic science research and casework has increased dramatically. This technique requires minimal to no sample preparation and has high-throughput capabilities. Therefore, it is increasingly used to address forensically relevant challenges, including those identified by the National Institute of Justice in the 2019 Report to Congress: Needs Assessment of Forensic Laboratories and Medical Examiner/Coroner Offices. These challenges result from the “legalization and decriminalization of marijuana,” and require the development of new strategies to test THC (delta-9-tetrahydrocannabinol, the major psychoactive component of Cannabis sativa) in a variety of complex matrices.
A typical DART-HRMS acquisition can be completed in under a few minutes, including calibration and data processing, and results in a mass spectrum revealing the chemical profile of the respective sample. When interrogated by DART-HRMS in positive-ion mode with no sample pretreatment, protonated masses consistent with cannabinoids (primarily THC/CBD at m/z 315) are readily detected, even in the midst of other ingredients present in the samples (e.g., fats, sugars, lipids) that typically wreak havoc on chromatography instrumentation. Therefore, a myriad of cannabinoid-infused sample types, including edibles, beverages, plant materials, personal-care products, and certified reference materials, can be analyzed and have been screened throughout this project. The results demonstrate that cannabinoids can be readily detected regardless of the matrix type. The research was also extended to the development of: (1) a method to triage complex cannabinoid-infused edibles and plant materials; and (2) validated quantification protocols using DART-HRMS.
Drugs in Bugs: Development of an Ambient Ionization Mass Spectrometry and Chemometrics Approach for the Revelation of the Presence of Drugs in Postmortem Samples Using Carrion Insects
Usually, when insects that have colonized decomposing remains are recovered in the course of a death investigation, they are used as a means to estimate time since death. However, this narrow focus belies the immense amount of information that can potentially be extracted from the entomological evidence. For example, in cases where remains have reached a level of decomposition incompatible with standard toxicological analysis practices, it is possible to glean information about drugs that may have been in the system of the decedent by detecting them in insects that colonized and consumed the tissue. Thus, the insect evidence can serve as a preserver of this important information if these chemical compounds or their metabolites can be detected.
Direct Analysis in Real Time-High Resolution Mass Spectrometry (DART-HRMS) is demonstrated here as a novel approach to extract toxicological information from insects. L. sericata (common green bottle flies) were fed beef liver laced with fentanyl derivatives at physiologically relevant concentrations. Flies were collected at all life stages from the freshly hatched larvae through to the emergence of adult flies and preserved in aqueous ethanol over the course of two weeks. Insect metabolome profiles were then generated for individual specimens using DART-HRMS. The profiles were subjected to kernel discriminant analysis in order to differentiate between those that consumed drug-laced liver verses those that did not. Significant profile differences were found at all life stages, but were especially prominent in the puparial casings, thus bringing value to an otherwise often overlooked form of entomological evidence.
Poster Presentation Abstracts
How Much Wood Would a Wood Chemist Analyze if a Wood Chemist Could Analyze
Wood Using DART-HRMS and Machine Learning
Mónica Ventura, Samira Beyramysoltan, Ph.D., Benedetta Garosi, Meghan Appley, and Rabi Musah, Ph.D.*
One of the concerns of wildlife forensics is the identification of endangered species, the trade of which is illegal. The Convention on International Trade of Endangered Species (CITES) was created to address the conservation of jeopardized wildlife by controlling their trade. While trade in fauna, including elephant tusks, rhinoceros horns, and pangolin scales, are well-recognized examples of wildlife crimes, there are a host of flora that are also severely trafficked. Dalbergia genus trees, also known as rosewood, serve as a case in point. Illegal trade of these species is common because they are highly prized for making exclusive furniture, cabinetry, musical instruments and artifacts. A current technique used by law enforcement to differentiate species of wood is direct analysis in real time-high resolution mass spectrometry (DART-HRMS), coupled with multivariate statistical analysis. Here, the added dimension of wood headspace analysis featuring solid phase microextraction (SPME) was used to generate data to complement that acquired using the conventional wood analysis technique. This could facilitate the development of “stand-off” approaches for the differentiation of wood species based on their volatiles profiles. Seventeen Dalbergia species were provided by the U.S. Fish & Wildlife Forensic Lab. The headspace volatiles of the wood samples were concentrated on SPME fibers and analyzed by DART-HRMS. A random forest classification model was developed to aid in the discrimination between the Dalbergia species by machine learning. The results show that this approach can be used as a technique for species identification of these illegally traded timber.
Ligand Dependent Redox-Coupled Spin Crossover Behavior of a
Five-Coordinate Cobalt (II) Salen for Electrochromic Applications
Charles McCabe, Peter H. Dinolfo
Spin‒crossover behavior in coordination compounds has
attracted a great deal of interest from researchers for its potential
applications in displays, sensors, data storage devices, and computer
processing. Our lab has previously described the synthesis and structure
of a five-coordinate cobalt complex where the spin-crossover behavior
can be controlled electrochemically. Herein, we examine the influence of
ligands such as pyridine, bromide, and imidazole on the redox‒coupled
spin-crossover behavior of this complex. Ligand binding and the
subsequent change in spin state are associated with a change in the
complex’s absorption profile and electrochemical behavior. Once a ligand
is bound to the metal center a significant cathodic shift in reduction
potential is observed. This shift correlates to the strength of the
sigma donor interaction between the ligand and the metal. By varying the
guest ligand we have established a correlation for the control of the
redox‒coupled spin-crossover behavior of this complex, allowing us to
tune these interactions for specific applications.