A rapid on-site fluorescence sensing platform for malachite green in an aqueous phase based on...

The residue of malachite green (MG) in water has serious toxic effects on the human body, so it is very important to establish a highly sensitive and convenient method for MG detection. In this study, a novel double-emission lanthanide MOF fluorescence probe (Eu-Zn-MOF) was designed for monitoring MG in water by post-synthetic modification (PSM) to Zn-MOF synthesized by a simple hydrothermal method. Eu-Zn-MOF exhibits excellent photoluminescence properties, making it suitable as a ratiometric fluorescence sensor (I₄₁₀/I₆₁₅) for the sensitive detection of MG. MG effectively quenches the luminescence of Eu³⁺ at 615 nm, while the luminescence of the Zn-MOF frame at 410 nm remains unaltered. The fluorescence sensing platform had a relatively wide linear range (0-30 µM), low detection limit (9.8 nM), high sensitivity, and rapid response time (within 1 min). At the same time, the recovery of actual samples was 90.2-107.0%, and the relative standard deviation (RSD) was ≤ 3.82%. Simultaneously, by combining the smartphone color recognition APP with RGB analysis, a portable smartphone auxiliary sensing platform was established to realize the visual detection of MG. This method provides a novel strategy for real-time monitoring of pollutants in the environment.