Developing a novel ultraselective and ultrasensitive label-free direct spectrofluorimetric nanobiosensor for direct highly fast field detection of explosive triacetone triperoxide

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BackgroundDirect detection of the notorious explosive triacetone triperoxide (TATP) is very difficult because it lacks facile ionization and UV absorbance or fluorescence. Besides, the current indirect methods are time-consuming and need a pre-step for TATP cleavage to hydrogen peroxide. Moreover, they commonly show significant false-positive results in the presence of some camouflage which limits their field applications. Herein, for the first time, a novel label-free field-applicable spectrofluorimetric nanobiosensor was developed for direct TATP detection using a novel activated-protein protected gold nanocluster (ABSA-AuNCs; QY = 28.3 %) synthesized by a combined protein-assisted-ultrasonication procedure. ResultsThe ABSA-AuNCs revealed a fluorescence spectrum centered at 330.0 nm which was significantly quenched by TATP (binding constant = 154.06 M-1; ΔG = −12.5 kJ mol−1; E(%) = 88.5 %). This phenomenon was used as a basis for direct TATP quantification, providing a working range of 0.01–40.0 mg L−1 and a detection limit of 6.7 μg L−1 which is the lowest LOD provided for TATP detection up to now. A %RSD of 0.9 % and 1.56 % was obtained for repeatability and inter-day reproducibility, respectively. The selectivity was checked against a variety of camouflages, revealing ultra-selectivity. Several synthetic samples prepared by several camouflages and real samples (clay soil and real water media) were analyzed, revealing quantitative recoveries of TATP. SignificanceDuring the production of the notorious explosive TATP, it can be discharged into water and soil. This novel method eliminated the false-positive results of traditional methods and is applicable for direct quantitative detection of camouflaged TATP and its residues in real soil and water samples in a highly short response time (2 min). The camouflaged TATP analysis is important for tracking the terrorist attacks in field conditions and analysis of soil and water can provide a first indication of the location of the production site.