Water-induced supramolecular self-assembly of porphyrin integrated with multivalent metal-organic framework for enhanced electrochemiluminescence and ultrasensitive aptasensing of 4-fluoromethamphetamine.

Aggregation-caused quenching (ACQ) and poor aqueous solubility severely restrict electrochemiluminescence (ECL) applications of polycyclic aromatic hydrocarbons (PAHs). Herein, a water-induced supramolecular self-assembly strategy is proposed to address these drawbacks. Via a simple reprecipitation route, representative PAH meso-tetrakis(4-carboxyphenyl)porphyrin (TCPP) forms ordered supramolecular aggregates driven by noncovalent interactions, which suppress π-π stacking and ACQ and achieve a low triggering potential of - 1.0 V. Iron-based MOF supported molybdenum disulfide (MIL-101@MoS2) is adopted as a multifunctional amplifier: reversible valence interconversion of Fe2+/Fe3+ and Mo4+/Mo6+ sustains continuous redox cycling to improve redox activity, while abundant oxygen vacancies accelerate electron transfer and coreactant activation for further ECL enhancement. After preparing MIL-101(Fe)@MoS2@TCPP nanoparticles (MMST), an ECL aptasensor is fabricated for 4-fluoromethamphetamine (4-FMA) determination relying on target-triggered cyanine dye displacement. This sensor exhibits an ultralow limit of detection of (1.87 × 10- 15 g/L) (S/N = 3) and a broad linear range from (1.0 × 10- 14 - 1.0 × 10- 6 g/L) g/L. It also shows favorable analytical results for real e-cigarette samples, with recoveries of 95.0-104.0% and relative standard deviations (RSD) less than 5.0%. This work offers a green route for high-performance PAH-based ECL luminophores and a reliable tool for rapid screening of emerging psychoactive contaminants in complicated food-related matrices.