Recent Advances in Ratiometric Fluorescence Methods for Environmental Pollutant Sensing

Abstract: In recent years, the development of convenient and rapid detection technologies has become an urgent priority due to the increasingly severe environmental pollution issues. Among various analytical approaches, the ratiometric fluorescence method (RFLM) is widely applied in the field of environmental pollutant sensing owing to the merits of high sensitivity and anti-interference ability. Firstly, unlike previous work, this review systematically reports the sensing modes of RFLM for the first time, concerning co-directional, contra-directional, and inconstant-constant variation modes. The sensing mechanisms of RFLM are also briefly outlined, such as aggregation-induced emission, intramolecular charge transfer, photoinduced electron transfer, fluorescence resonance energy transfer, and inner filter effect, as well as the molecular imprinting technique. In addition, we discuss the enhancement of artificial intelligence (AI) for the analytical performance of RFLM. Subsequently, the review provides a detailed summary of recent advances over the past five years in RFLM-based applications, with a focus on luminescent materials, including inorganic nanomaterials and organic fluorophores. Finally, we propose the current challenges associated with RFLM in environmental pollutant sensing and outline potential directions for future research and development.