MOF-based differential fluorescent sensing array for fingerprint discrimination and quantitative detection of phosphates in complex matrices

Accurately distinguishing structurally analogous phosphate species represents a persistent analytical challenge in biomedical and environmental analysis. To address this, we developed a novel fluorescent sensor array for the effective multiplexed identification of phosphates based on a library of metal-organic frameworks (MOFs). Three MOFs were synthesized from the ligand 2,5-dihydroxyterephthalic acid (DHTP) and Zn 2+ , Co 2+ , and Cu 2+ . The fluorescence of these MOFs, initially quenched via photoinduced electron transfer (PET), is specifically restored upon phosphate exposure via a dual-response mechanism involving the surface esterification with hydroxyl groups and competitive coordination to metal nodes, leading to framework disassembly. Differential binding affinities between phosphates and the three metal centers generate unique fingerprint-like response patterns across the three-channel array. By integrating with linear discriminant analysis (LDA), we achieved rapid and accurate discrimination of multiple phosphate species, including nucleotides (AMP, ADP, ATP, H 4 P 2 O 7 ) and inorganic phosphates with 100% classification accuracy. Moreover, quantitative analysis results showed that the method has a broad linear range of 0.5–8 μM with a low limit of detection (LOD) of 0.051 μM for H 4 P 2 O 7 , 0.342 μM for ATP and 0.105 μM for NaH 2 PO 4 . This label-free, washing-free sensing protocol demonstrates high sensitivity, excellent reproducibility, and reliable performance in complex matrices, offering a robust and versatile platform for applications requiring precise phosphate differentiation, such as clinical diagnostics and environmental monitoring.