FRET- and PET-based sensing in a single material: expanding the dynamic range of an ultra-sensitive nitroaromatic explosives assay.

A polyethylenimine polymer derivatized with pyrene moieties suitable for the fluorescence-based detection of nitroaromatic explosives (NAC) in aqueous systems is described. The system exhibits an exceptionally wide dynamic sensing range of 7 orders of magnitude (from 33 ppt to 225 ppm TNT or Tetryl). This broad range was achieved by the combination of FRET and PET sensing mechanisms in a single material. The sensing material is suitable for a paper strip assay. Simplicity, selectivity, and the wide dynamic range suggest this material for explosives detection in the field.