High-Sensitivity Fluorescence Detection of Malachite Green in Aquaculture Using a Zirconium-Based Metal-Organic Framework PCN-128
A fluorescent metal-organic framework (MOF), PCN-128, was synthesized via a solvothermal method using zirconium tetrachloride (ZrCl4) as the metal source and tetrakis[4-(4'-carboxyphenyl)phenyl]ethylene (H4ETTC) as the organic linker. The resulting material exhibited regular morphology, high crystallinity, strong luminescence, and good stability. PCN-128 was employed as a fluorescent probe for the trace detection of malachite green (MG), a banned veterinary drug, in aquaculture water and freshwater fish tissue. The probe demonstrated exceptional selectivity toward MG among 13 veterinary drugs and robust anti-interference performance against 16 anions, 16 cations, and 12 additional veterinary drugs. The method achieved a broad linear detection range from 0.0 to 7.0 μmol·L−1 with a limit of detection (LOD) of 2.73 nmol·L−1. Spike-and-recovery experiments in three aquaculture water samples and one freshwater fish sample yielded recoveries between 89.80% and 113.7%, with relative standard deviations (RSD) not exceeding 2.59%. These results confirm that the developed method is accurate, reliable, and suitable for routine monitoring of MG residues in aquaculture water and aquatic products, addressing a critical gap in food safety surveillance.