An Al3+ Ions-Responsive Blue Emitting Ionic Liquid-Based Nano-Optode and Its Implications for the Detection of 2, 4, 6-Trinitrophenol

Abstract

This report introduces a novel IL-mediated fluorescence turn-on photoluminescence nanooptode designed for the highly sensitive and selective monitoring of aluminium ions (Al³⁺).The fabricated nano-optode exhibited pronounced optical responsiveness to Al³⁺ ions, with an exceptionally low detection threshold in the picomolar range, attributed to chelationenhanced fluorescence (CHEF) within the IL, demonstrating significant progress beyond the current state of the art. To enable on-site analysis, a portable paper-strip solid sensor was fabricated using the nano-optode formulation, allowing for instantaneous visual Detection of Al³⁺ ions contamination in aqueous samples. Furthermore, the IL-based Al³⁺-complex served as an intermediate bridge in a cascade sensing system for the subsequent Detection of picric acid, demonstrating dual recognition. A smartphone-based fluorometric platform was also developed for quantitative analysis, enabling real-time, user-friendly monitoring without reliance on high-end laboratory instruments. This investigation unveils a novel approach for fabricating photonic IL-based nano-optodes as a cost-effective, highly responsive, and portable sensing platform for environmental and security applications.