In Situ Generated Dye@MOF/COF Heterostructure for Fluorescence Detection of Chloroquine Phosphate and Folic Acid via Different Luminescent Channels

Metal-organic framework (MOF) and covalent-organic framework (COF) hybrid materials can combine the unique properties of MOF and COF components, and their applications in fluorescence sensing have attracted more and more attention. Herein, ZIF-90 is grown on 3D-COF by a simple in situ growing method in which the 7-amino-4-methylcoumarin (AMC) is encapsulated in ZIF-90 to construct a fluorescent sensor. Chloroquine phosphate (CQP) can coordinate with Zn²⁺ to decompose the ZIF-90 and release AMC. At 365 nm excitation, the ratiometric fluorescence signal AMC/3D-COF (I₄₃₀/I₅₉₈) increases linearly with CQP in a linear range of 4 × 10^-5 to 4 × 10^-4 M in urine. Under 340 nm excitation, quantitative analysis of CQP in the serum (3 × 10^-6 to 4 × 10^-5 M) is based on the fluorescence intensity of Zn-CQP/3D-COF (I₃₈₄/I₅₉₈). In addition, AMC@ZIF-90/3D-COF (1) exhibits high anti-interference and selectivity in sensing of FA with a "turn off" mode, with a correlation range of 1 × 10^-5 to 1 × 10^-3 M. The fluorescence color changes triggered by CQP under different excitation conditions, and the different fluorescence responses caused by CQP make it a highly secure anticounterfeiting platform. The synthesized dye@MOF/COF hybrids not only provide a new way to integrate multiple emission to design fluorescent probes for differentiation detection but also offer ideas for the design of anticounterfeiting platforms.