Screening For Biological Agents In Powder Mixtures With The Illuminatir

Introduction
In this time of heightened national security, identifying the presence of biological agents in suspicious powder mixtures is a serious issue. The state National Guard Weapons of Mass Destruction Civil Support Teams (WMD-CSTs) and Public Health Laboratories that are charged with this mission need reliable and rapid analytical capabilities. One approach is to combine polarized light microscopy (PLM) with infrared (IR) microspectroscopy to characterize powdered mixtures on both microscopic and molecular levels. The synergism of these analytical techniques provides significantly more information than can be derived from either technique alone. Whereas PLM can elucidate optical and morphological characteristics of solids, IR spectroscopy provides highly specific information on the covalent bonds within molecules. In fact, the IR spectrum of a substance is often called its "fingerprint," and can be used to identify substances of unknown origin. The IlluminatIRTM accessory merges IR microspectroscopy with a conventional infinity-corrected light microscope, and its QualIDTM software performs an automated analysis of the spectra to easily identify unknown samples. In this study, bacillus thuringiensis (BT), a bacterium that is harmless to humans but is a simulant of deadly bacillus anthracis (Anthrax), was analyzed within a matrix of non-biological solid materials to demonstrate the union of these techniques.