Copper(I)-driven colorimetric-fluorometric detection of triacetone triperoxide (TATP) using eco-friendly carbon dots

Triacetone triperoxide (TATP) is a homemade potent explosive commonly used in terrorist attacks. The lack of a distinct chromophore group in its structure, unlike other explosives, poses a significant challenge for its detection. To address this issue, we propose a novel approach centered on a Cu(I)-driven Fenton-like reaction, which involves simultaneous fluorometric and colorimetric determination of TATP in the same reaction tube. The analytical system involves Cu^I, a precursor metal cation requiring acidic solubility, oxygen- and nitrogen-doped carbon dots (ascorbic acid-urea-CDots) (AU-CDots), the color reagent N,N-dimethyl-p-phenylenediamine (DMPD), and TATP in the same reaction tube. The hydrochloric acid required to dissolve Cu^I hydrolytically cleaves TATP, and the resulting hydrolysate H₂O₂ undergoes a Fenton-like reaction with Cu^I, producing Cu^II and hydroxyl radical (^•OH). The resulting Cu^II selectively interacts with the AU-CDots, quenching fluorescence, while ^•OH interacts with DMPD, producing a colored radical cation (DMPD^•+). Thus, TATP can be determined simultaneously by both fluorometric and colorimetric methods. The method provides a TATP detection limit (LOD) of 3.0 nmol L^-1 and 10.0 nmol L^-1 for the fluorometric and colorimetric assays, respectively. Furthermore, AU-CDots exhibit catalytic activity both in fluorometric and colorimetric measurements. In both methods, while the presence of metal cations, anions, camouflage materials, and explosive mixtures did not affect TATP recoveries (94.9 %-105.3 %), almost quantitative retrievals (97.5 %-105.2 %) were obtained from soil samples contaminated at different levels.