Real-Time Label-Free Detection of Suspicious Powders Using Noncontact Optical Methods

In situ assessment of suspicious powders within inorganic matrices, with particular emphasis on powders of biological origin, is currently limited to detection by biochemical methodologies that react with monomers such amino acids, nucleic acids, lipids or macromolecule compounds comprised of these basic subunits. These current methods include immunoassays or PCR, both of which require expensive equipment and reagents with limited shelf life and restrictive conditions for storage and use, and considerable time. Current optical methods such as Raman spectroscopy using excitation in the near IR at 785 nm or visible at 532 nm, have not been able to detect or distinguish biological materials. Until recently, these have been the only classes of handheld instrumentation available to address the problem of identifying suspicious powders in near real-time and in situ at the site of an incident. We propose to develop and demonstrate an emerging handheld technology that employs a fusion of deep UV excited Raman and fluorescence spectroscopic methods that enable real-time, in situ, detection and classification of trace amounts of biological material: without the need for reagents, labels or other consumables; without contact or disturbing the suspicious powder and subsequent need for decontamination of instrumentation or spread of the powder. The original document contains color images.