Acriflavine-modified UIO-66 ratiometric fluorescent sensor for highly selective and fast detection of hypochlorite in water

[Display omitted] •A dual-emission ratio fluorescence probe was invented for the detection of ClO−.•The probe achieved sensitive, fast and stable detection of ClO−.•The ClO− level was monitored by the ratio values in the green and blue channels.•This approach offered a new way to detect ClO− in surface water and drinking water. Hypochlorite (ClO−) as a kind of highly toxic pollutant has garnered significant interest in detection methods, highlighting the pressing need to develop intelligent functional materials for the qualitative and quantitative analysis of ClO− in aqueous solutions. Herein, a ratiometric fluorescent sensor was prepared by the combination of acriflavine (Acr) and UIO-66 via a post-synthetic modification strategy. Acr/UIO-66 exhibited both high crystallinity typical of metal–organic frameworks and demonstrated good fluorescent and thermal stability. Additionally, Acr/UIO-66 functioned effectively as a dual-responsive fluorescent platform for detecting ClO− in domestic drinking and surface water samples. This material displayed high sensitivity, exceptional selectivity, and superior anti-interference capabilities, along with fast respond time (60 s), a wide pH range (4.0–7.0), high recoveries (94.46–118.00 %), a broad linear range (0–28 µmol L−1) and low detection limits (0.74 µmol L−1). This study broadened the potential applications of fluorescent metal–organic frameworks and presented a feasible solution for water quality monitoring.