Photoinduced electron transfer-driven dual-ligand MOF fluorescence sensor for highly selective and sensitive detection of periodate in complex water samples

Periodate (PI) is widely used in advanced oxidation processes (AOPs) due to its unique oxidizing properties. However, excessive residual PI can negatively impact water quality. Here, we report a novel dual-ligand metal-organic framework (MOF), In-MOF, which exhibits excellent performance for PI detection in complex environmental water samples. In-MOF was constructed using 2-aminoterephthalic acid (BDC-NH 2 ) and biphenyl-3,3′,5,5′-tetracarboxylic acid (H 4 BPTC) ligands and features internal molecular hydrogen bonding and photoinduced electron transfer (PET) effects, significantly enhancing its selectivity and stability in aqueous environments. In its native state, the fluorescence of In-MOF is quenched due to its intrinsic PET effect. However, upon interaction with PI, the disruption of internal hydrogen bonds and inhibition of the PET process results in the emergence of bright blue fluorescence. Experimental results demonstrate that In-MOF maintains high selectivity for PI even in the presence of common oxidants and by-products (such as iodate) found in industrial processes. Furthermore, a paper-based platform was developed for on-site PI detection, further expanding the application potential of this MOF-based sensor for environmental monitoring. These findings highlight In-MOF as an efficient, cost-effective, and environmentally friendly solution for periodate detection across various water sources.