A Single-Component Ce-MOF Sensor for Dual-Target Sensing: Ratiometric/Colorimetric Detection of Vitamin B2 with Smartphone Integration and Fluorescent Off-to-On Detection of Vitamin B6.

Vitamin B2 (VB2) and Vitamin B6 (VB6) are essential micronutrients for maintaining normal physiological functions. Deficiency and excessive intake of vitamins can lead to significant health issues. Herein, a single-component cerium-based MOF sensor (Ce-MOF), {[Ce2(BTB)2(DMF)2]•2DMF•2.5H2O}n is synthesized via solvothermal methods. The as-prepared Ce-MOF exhibits excellent water stability and distinct ligand-centered emission, which serves as an efficient dual-target sensor, enabling highly selective and sensitive ratiometric and colorimetric detection of VB2, as well as fluorometric detection of VB6. Upon addition of VB2, Ce-MOF exhibits a new emission peak at 527 nm, accompanied by a visible fluorescence color change from blue to yellow-green. The quenching constant is 8.41 × 104 M-1, and the detection limit is as low as 0.052 μM. In the case of VB6, the emission peak gradually red-shifts to 395 nm, with a quenching constant of 2.06 × 104 M-1 and a detection limit of 0.355 μM. Moreover, a Ce-MOF-embedded portable hydrogel combined with smartphone-assisted RGB analysis is fabricated, enabling visual and quantitative detection of VB2 and achieving excellent recovery (92.4-106.6%) in vitamin tablets, banana extracts, and sugar. These results highlight the potential of Ce-MOF as an efficient and practical dual-target sensor for nutritional analysis.