Encapsulating Fluorophores in a Lanthanide MOF for Ratiometric and Colorimetric Luminescence Detection of Sodium Dehydroacetate with Three Fluorescence Signals in Food Samples

Abstract Sodium dehydroacetate (Na-DHA) is widely employed as a food preservative; excessive intake poses potential risks to human health, and the accurate detection of Na-DHA in food is very important. Herein, we develop a dual-emission Tb-MOF and its rhodamine B (RhB)-encapsulated derivative (Tb-MOF@RhB) with triple-emission properties, which achieves the ratiometric fluorescence sensing of Na-DHA. Tb-MOF enables highly selective and sensitive ratiometric fluorescence detection of Na-DHA with a low limit of detection (LOD = 3.64 μM) and satisfactory recoveries (96.12–106.71%) in food samples. Taking advantage of hydrogen-bonding interactions with Na-DHA, Tb-MOF@RhB displays a distinct ratiometric and colorimetric fluorescence response via three emission channels, accompanied by a visible color change from yellow to green, with LODs of 2.20 μM (I546/I439) and 6.17 μM (I585/I439). Moreover, Tb-MOF@RhB can also enable quantitative detection of Na-DHA in food samples with high recoveries of 95.10–105.45%. Furthermore, portable smartphone-assisted detection platforms were developed to facilitate high-precision on-site sensing of Na-DHA.