Smartphones and paper-assisted detection of TNP using a cationic perylene diimide derivative in 100% aqueous media

2,4,6-trinitrophenol (TNP) is an environmentally deleterious substance with high toxicity and explosibility. It is of great significance for environmental protection and public health to establish a rapidly on-site monitoring method for perilous TNP. Current methods for detecting TNP mainly rely on traditional laboratory analysis lacking rapid detection through intelligent modes. Herein, we construct a smartphone recognition based fluorescence sensing system via the supramolecular assembly of a perylene probe to quantify TNP. The sensing platform consists of a fluorescent probe based on quaternary ammonium functionalized perylene (PDI-BTMA), as the TNP-response recognition element, and smartphones as optical signals receptors bringing simpleness, celerity, and portability for TNP monitoring. The sensor reveals dual output signals of color and fluorescence in response to TNP. The results show that the optical responses of PDI-BTMA can be attributed to the formation of the supramolecular complex (PDI-BTMA/TNP) via non-covalent interactions including static electricity, hydrophobic interaction, charge transfer, and 7C-7C stacking. It shows a wide linear range for TNP of 200-1200 nM with a detection limit of 9 nM. In addition, we successfully made portable PDI-BTMA fluorescence paper. The RGB value of fluorescence color was also collected by using the smartphone-assisted sensing platform, and the G/B channel values show a linear relationship with TNP concentration in 0.1-50 mu M, with the lowest detection concentration of 48.4 nM. Additionally, it could be successfully utilized for quantitative TNP monitoring in environmental water and soil samples, which achieved a greater recovery rate in the range of 99-110%. This research integrating the PDI-BTMA probe with a smartphone firstly presents a new strategy for real-time and on-site monitoring of TNP in the environment.