More rigorous and advanced methods for the analysis of evidence are needed in forensic science and have been called for by the National Academies of Science in the 2009 report Strengthening Forensic Science in the United States. Trace chemical analyses—including drugs of abuse, explosives and accelerants, residues of human decomposition, and crime scene hazards—require more sensitive and robust methods, especially in field environments. Another area of concern is that current analytical methods for drug testing are not agile or well-resolved enough to keep pace with the numerous and constantly evolving synthetic drugs in use today. Portable proton transfer reaction mass spectrometry (PTR-MS) is a technology well suited to address these challenges. We seek applicants for a postdoctoral fellowship to lead a research project exploring the use of on-line PTR-MS in field applications relevant to forensic science. Two potential project areas are (1) the detection of drugs and metabolites in the breath for universal roadside intoxication testing and (2) field measurements and monitoring for antibiotic resistance in animal agriculture.
A mass spectrometry approach to roadside screening for intoxication would be comprehensive and more robust to trends in drugs of abuse, like synthetic cannabinoids, than current methods. Many of these compounds and their metabolites can be found in the breath after smoking or by partitioning from blood in the alveoli of the lungs. This project will involve the design of a surrogate fluid to represent human expired breath. The surrogate will then be used to apply on-line PTR-MS to the detection of model drug compounds in a simulated field environment. Experiments could also explore the effects of variables like simultaneous alcohol intoxication, or extend to other roadside investigations, e.g. screening for contraband in a vehicle. The project may also investigate the partitioning behavior of these compounds between the body and the breath using surrogates for fatty tissue, blood, and mucus.
Antibiotic drugs are widely used in animal agriculture, and antibiotic resistance is currently one of biggest public health issues in the United States. Currently, the process of bacterial culture (testing to find what bacteria are present) and sensitivity (testing to find what kind of antibiotic will kill the bacteria present) takes 5 to 10 days and access to a laboratory to complete. This project will involve the application of PTR-MS to real-time collection and determination of bacterial loads from air sampling of bacterial metabolites in situ. The first goal of the project will be to characterize the volatile organic chemical fingerprints of various bacteria using PTR-MS. We will then optimize a rapid, noninvasive workflow for bacteria commonly seen in agriculture.
Other projects in forensic science are also of interest, including the use of real-time PTR-MS to locate human remains and to identify potential hazards at a crime scene to reduce risks (of accidental drug overdose, for example) to first responders and forensic technicians. The successful candidate will have a Ph.D. in chemistry or engineering and interest in technology transfer/stakeholder engagement. Headspace sampling with preconcentration, nuclear magnetic resonance, and other analytical techniques will also be available to the researcher in support of the project.
antibiotic resistance; breath; drug detection; forensic science; in-the-field; mass spectrometry; partitioning; volatile