Infrared Laser Ambient Mass Spectrometry

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With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Murray and his group at Louisiana State University and Agricultural and Mechanical College in Baton Rouge will develop new instrumentation for rapid chemical and biochemical analysis under ambient conditions. The instruments developed under this project will have applications in forensics, transportation security, medicine, and other diverse areas. Dr. Murray's group will use pulsed infrared lasers to ablate material directly from samples in the environment. The ablated material is captured in a small solvent droplet or on a sample target for mass spectrometry analysis. Unlike conventional mass spectrometry, the bulk sample does not need to be processed and loaded into the instrument; the laser removes only a small portion for analysis. The dual goals of the research are a fundamental understanding of the infrared laser ablation process and the application of this knowledge to the design and implementation of novel chemical analysis instrumentation. The fundamental issues of laser ablation are the size and quantity of the ablated material and the dependence on the laser wavelength, pulse energy, and sample composition. High-speed photography, broad-spectrum particle sizing, and finite element modeling will be used to probe and optimize the material removal process. Ambient laser ablation sampling will be used for biochemical imaging and remote robotic sampling. Laser ablation sampling allows component separation between sampling and analysis for expanded dynamic range. The remote robotic sampling stage will sample large three-dimensional objects for diverse applications such as real-time mass spectrometry during a surgical procedure or checkpoint baggage analysis for explosive residue. The educational component of this project continues the focus on expanding educational opportunities for underrepresented groups that is the highlight of the LSU chemistry program. A hands-on mass spectrometry demonstration will also be developed that will show students the power and utility of mass spectrometry while linking to the fundamental chemistry and physics behind the technique.