Smartphone-assisted radiometric fluorescent probe for visual detection of F−

The fluoride ion (F − ) is a vital trace element required by biological systems to maintain normal physiological functions, playing a crucial role in development and bone metabolism. However, excessive accumulation of F − can result in fluorosis, arthritis, and other adverse health effects. Critical development of precisely discerning fluoride ion detection systems is imperative. In this work, a zirconium-based metal-organic framework (Zr-MOF) was synthesized via a green hydrothermal process using zirconium chloride and tetrafluoro terephthalic acid (TFTPA) as precursors. The obtained Zr-MOF was combined with curcumin (Cur) to create a fluorescent probe for F − recognition. This probe exhibits superior anti-interference ability and high selectivity, along with a notable sensitivity. The fluorescence intensity (FI) ratio of Cur@Zr-MOF shows a linear reduction with increasing F − concentration, spanning a range 0–40 μM, and achieves a detection limit as low as 0.03 μM. The blue fluorescence of Zr-MOF is significantly attenuated under 365 nm ultraviolet radiation (UV) in the presence of F − , resulting in a notable color change of Cur@Zr-MOF solutions within the 0–40 μM F − range. This phenomenon can be utilized for smartphone-assisted visual detection. The probe's practicality was confirmed via spiked water sample analysis in the 0–36 μM range, with recoveries of 96.8–101.8 %. The Cur@Zr-MOF proposed in this study provides a promising platform for the detection of F − , which is expected to be applied in environmental monitoring and public health.