Tailored MIL-125(Ti)-NH ₂ for sensitive detection of 2,4,6-trinitrophenol: a post-synthetic approach

Schiff-base functionalised metal-organic framework (MOF), MIL-125(Ti)-Sal, was fabricated through a solvothermal synthesis technique and employed to detect 2,4,6-trinitrophenol (TNP) at ultra-trace concentrations in the aqueous samples. π-electron rich moiety and hydrogen-bond accepting site in the linker enabled framework to efficiently interact with TNP exhibiting efficient fluorescence quenching via turn-off mechanism with a low limit of detection of 1.20 μM. Fabricated MOF demonstrated exceptional selectivity towards TNP, maintaining its discriminatory sensing capabilities even in the presence of structurally similar nitroaromatic explosives (NEs) coexisting in the aqueous phase. Molecular interactions, Resonance energy transfer (RET), and Density functional theory (DFT) calculations comprehend the sensing mechanism. Validation using spiked aqueous samples, confirmed the prepared MOF as a robust and effective platform for selective TNP detection and quantification.