A Photoluminescence-Based Field Method for Detection of Traces of Explosives

We report a photoluminescence-based field method for detecting traces of explosives. In its standard version, the method utilizes a commercially available color spot test kit for treating explosive traces on filter paper after swabbing. The colored products are fluorescent under illumination with a laser that operates on three C-size flashlight batteries and delivers light at 532 nm. In the fluorescence detection mode, by visual inspection, the typical sensitivity gain is a factor of 100. The method is applicable to a wide variety of explosives. In its time-resolved version, intended for in situ work, explosives are tagged with europium complexes. Instrumentation-wise, the time-resolved detection, again visual, can be accomplished in facile fashion. The europium luminescence excitation utilizes a laser operating at 355 nm. We demonstrate the feasibility of CdSe quantum dot sensitization of europium luminescence for time-resolved purposes. This would allow the use of the above 532 nm laser

Synthesis of asymmetrically substituted cyclen-based ligands for the controlled sensitisation of lanthanides

A series of unsymmetrical cyclen-based ligands incorporating an antenna and a quencher have been prepared for the complexation of the visible- (Eu, Tb) and near IR-emitting (Nd, Yb) lanthanides. Eu and Tb were sensitised with coumarin 2, and Nd and Yb with rhodamine. Both antennae were paired with nucleoside (uridine and adenosine) quenchers. The interaction between the quencher and the antenna can be regulated by the addition of the complementary base or DNA to the complexes, resulting in changes in the lanthanide luminescence intensity and lifetime