Chemiresistive Device for the Detection of Nitroaromatic Explosives Based on Colloidal PbS Quantum Dots

Abstract

Semiconductor quantum dots have been recently employed as luminescent probes for the detection of hazardous nitroaromatic compounds. Despite the high sensitivity, such detection systems involve laboratory procedures and employ complex instrumentation. Here, we demonstrate the use of colloidal PbS quantum dots as the main component of a chemiresistor for the detection of nitroaromatic compounds. The proposed device is low-cost, reusable, and produces an electric signal that can be acquired with off-the-shelf electronic components. In this paper, we demonstrate the operation of the proposed device and we discuss its sensing mechanism. We also show the sensor's response to nitrobenzene in the 65 ppb−16 ppm range, estimating a theoretical detection limit of 2 ppb.

A metal complex based fluorescent chemodosimeter for selective detection of 2,4-dinitrophenol and picric acid in aqueous media

“…The K SV , K a and LOD values were calculated by comparing the fluorescence intensity obtained for 1 in the presence and absence of DNP/PA as reported earlier in the literature. 6–45,63 The fluorescence quenching titrations were carried out in pure water by placing 3 mL (20 μM solution) of 1 in a quartz cuvette of 1 cm path length. Then, a methanolic solution of either DNP or PA (0–2.6 equiv.)…”

“…hydrogen bonding, metal–ligand coordination, electrostatic interactions) have been taken into consideration. 6–45 As chemodosimeters are changed to drastically different species while exhibiting the sensing property, the concerned process is irreversible. 46 Nonetheless, highly selective fluorescent chemodosimeters for biologically important metal ions ( e.g.…”

“…As sensing of nitroaromatics is a field of great interest, several fluorescent chemosensors for nitroaromatics have been reported. 6–45 We have found that in only one case, the authors mentioned and explained the sensor as a fluorescent chemodosimeter. 13 The concerned compound is a small organic molecule which detects picric acid in 1 : 9 H 2 O : CH 3 CN.…”

“…In general, for mechanistic interpretation of the sensing of any analyte, single crystal structural evidence of the final association complex between the analyte and probe plays a crucial role in justifying the mechanism. In this regard, it is worth mentioning that although there are a large number of reported fluorescent chemosensors for nitroaromatics, 6–45 characterizing the sensor⋯nitroaromatic association complexes by single crystal X-ray structure determination has been possible only in some limited cases. 6–11,29–31 Notably, the single crystal X-ray structures of the sensor⋯nitroaromatic association complexes for the already mentioned fluorescent chemodosimeters have not been reported.…”

“…For practical purposes, the performance of fluorescent probes, prepared by easy synthetic methods, in aqueous media is highly desirable. A wide range of fluorescence materials based on small organic molecules, [6][7][8][9][10][11][12][13][14][15][16][17][18] organic polymers including conjugate polymers, 19,20 discrete metallo-organic coordination compounds, [21][22][23][24][25][26][27][28][29][30][31] coordination polymers including MOFs [32][33][34][35][36][37][38][39][40][41] and carbon or quantum dots [42][43][44][45] have been reported for the detection of nitro explosives. The majority of these materials are efficient in organic media and their preparation involves multistep procedures with high temperature and low yield.…”