Aerosol Plasmon-Enhanced Laser Desorption Ionization

Aerodyne Research, Inc. (ARI) and The University of Massachusetts at Amherst will collaborate to develop a novel technique for efficient mass spectrometric analysis of high molecular weight analytes such as proteins and polymers. Laser desorption and ionization with minimal analyte fragmentaton will be carried out on metal nanoparticle substrates in a particle beam sampled by Aerodyne’s proprietary aerosol mass spectrometer (AMS). Aerosolizing a solution of the molecules of interest together with suspended nanoparticles will allow rapid, real-time sampling. The initial aerosol particles will be dried in a gas flow, and the resulting sample particles composed of analyte molecules and nanoparticles will be sampled into the AMS. The coated nanoparticles intersect a laser beam inside the AMS ion formation chamber where the surface-bound molecules are desorbed, ionized, and detected with a time-of-flight mass spectrometer. Nanoparticles have been shown to have significant advantages in these applications, including selectivity of adsorption, and enhancement of desorption via surface plasmon resonance (SPR) effects. Bypassing the substrate preparation steps in conventional matrix assisted laser desorption and ionization (MALDI) will be of great importance in the areas of chemical and biological weapons detection, and have great commercial potential in the pharmaceutical, biomaterials, polymer and catalysis industries. BENEFIT: Analytical methods that are sensitive, selective and as broadly applicable as possible are required for identification of biological and chemical weapons. A post-attack, hospital-based instrument should provide information about the whole spectrum of threats, from chemical weapons, through protein and nonprotein toxins, that is, relatively low-mass nonvolatile substances such as saxitoxin and palitoxin, and extending to intact microorganisms such as viruses, vegetative bacteria and bacterial spores, and fungi. A "universal detector" covering all volatile and nonvolatile chemical and biological warfare agents is the ideal, and mass spectrometry is currently the only viable technique on which to base such a device. ARI’s proprietary technology, the Aerosol Mass Spectrometer (AMS), provides the means to achieve this development. In Phase I of this project, we will demonstrate the feasibility of applying ARI’s AMS technology to develop a real-time sampling system for mass spectrometry of low vapor pressure, complex molecular materials. At the completion of Phase II, we anticipate we will have developed a prototype of an instrument capable of rapid mass spectrometric measurements of molecules important in a number of critical applications.