The concentration of the chemical vapors emanating form landmines is very low. The equilibrium vapor concentration above pure, crystalline TNT at room temperature is approximately 70 ng/liter. It has been estimated that the TNT concentration in the air over a buried TNT-containing landmine is three to six orders of magnitude less than this value. TNT vapor concentrations three orders of magnitude less than equilibrium are difficult to detect with research quality laboratory instruments and are beyond the capabilities of most commercially available field-portable instruments. Hence, new ultra-sensitive detection technologies for explosives are needed. Collaborators at the MIT have synthesized novel fluorescent polymers that have been implemented as sensory materials in a landmine detection system. When vapors of nitroaromatic compounds of the type found in most landmines bind to thin films of the polymers, the fluorescence of the films decreases. A single molecular binding even quenches the fluorescence of many polymer repeat units, resulting in an amplification of the quenching. Analyte binding to the films is reversible, so the films can be reused. A prototype sensor package has been developed that response almost immediately to sub-picogram quantities of target nitroaromatics. The prototype is portable, is lightweight, has low power consumption, is simple to operate, and is relatively inexpensive. Improvements in the sensitivity of the package are expected. A sample preconcentrator is also being developed for use when the concentration of target analytes is to low to be sensed directly.