Selective Detection Of Explosives Research Articles

Poly(thymine)-CuNPs: Bimodal Methodology for Accurate and Selective Detection of TNT at Sub-PPT Levels.

Accurate, sensitive, and selective detection of explosives is of vital importance in antiterrorism and homeland security. Fluorescence sensors are prevalent for sensitive and fast in-field explosive detection but are sometimes compromised by accuracy and stability due to the similar structures of explosives, photobleaching, and complex sample matrixes. Herein, we developed a first bimodal methodology capable of both sensitive in-field fluorescence detection and accurate laboratory mass spectrometric quantification of 2,4,6-trinitrotoluene (TNT) by utilizing the characteristic fluorescent and mass spectrometric response of copper nanoparticles (CuNPs). An excellent selectivity was also realized by involving aptamer recognition. The methodology is capable of detecting TNT at subpart per trillion (PPT) levels, with a detection limit of 0.32 pg mL-1 by inductively coupled plasma mass spectrometry (ICPMS) and 0.17 ng mL-1 by fluorimetry. The signal response was accurate and stable for at least 60 days by ICPMS. Thanks to the biospecificity of the aptamer, this bimodal methodology is potentially applicable to a large panel of explosives.

Luminescent metal–organic gels with tetraphenylethylene moieties: porosity and aggregation-induced emission

To develop luminescent gels, a series of metal–organic gels have been successfully synthesised based on trivalent metal ions (Al3+, Cr3+, Fe3+, Ga3+, and In3+) and tetrakis(4-carboxyphenyl)ethylene (H4TCPE) that has aggregation-induced emission (AIE) features. Among these gels, the Al-TCPE gel has both high hierarchical micro- and mesoporosity and AIE effect. The Al-TCPE aerogel consists of metal–organic framework nanocomponents as revealed by TEM and PXRD, which contribute to its high microporosity. Using tetraphenylethylene as a building block endows the Al-TCPE gel with AIE photoluminescence. The Al-TCPE gel shows potential in the selective detection of explosives with picric acid chosen as a model explosive.

Hierarchically Imprinted Porous Films for Rapid and Selective Detection of Explosives

On the basis of the combination of colloidal and mesophase templating, as well as molecular imprinting, a general and effective approach for the preparation of hierarchically structured trimodal porous silica films was developed. With this new methodology, controlled formation of well-defined pore structures not only on macro- and mesoscale but also on microscale can be achieved, affording a new class of hierarchical porous materials with molecular recognition capability. As a demonstration, TNT was chosen as template molecule and hierarchically imprinted porous films were successfully fabricated, which show excellent sensing properties in terms of sensitivity, selectivity, stability, and regeneracy. The pore system reported here combines the multiple benefits arising from all length scales of pore size and simultaneously possesses a series of distinct properties such as high pore volume, large surface area, molecular selectivity, and rapid mass transport. Therefore, our described strategy and the resulting pore systems should hold great promise for various applications not only in chemical sensors, but also in catalysis, separation, adsorption, or electrode materials.