Zearalenone (ZEN) contamination in grains poses a serious threat to human and animal health, yet existing imaging-based platforms for rapid visualized detection remain limited by insufficient sensitivity, limited luminescence efficiency, and poor signal stability, hindering further practical applications. Herein, a portable smartphone-assisted electrochemiluminescence (ECL) imaging platform was developed for ultrasensitive and visualized detection of ZEN based on protamine-enhanced 6-aza-2-thiothymine-stabilized gold nanoclusters (Prot/ATT-Au NCs) synthesized by a protein-assisted assembly strategy. The resulting Prot/ATT-Au NCs achieved a 108-fold enhancement in ECL intensity relative to bare ATT-Au NCs and demonstrated an ECL efficiency approximately 5.01-fold higher than that of the benchmark Ru(bpy)32+ system, enabling naked-eye-visible green ECL emission. This enhancement was attributed to Prot-induced hydrogen-bonding and electrostatic confinement that suppressed nonradiative decay and facilitated radiative transitions. Integrated with catalytic hairpin assembly amplification, the developed ECL imaging system allowed ZEN to be visually quantified over a wide linear range of 1 pg/mL to 10 μg/mL with a detection limit of 0.38 pg/mL, along with excellent specificity, stability, reproducibility, and real-sample recoveries. Furthermore, it was applied for the determination of ZEN in naturally contaminated corn samples. This work provides a facile strategy for engineering high-performance ECL emitters and offers a robust route toward portable food safety monitoring.
Tingting Han, Jinyang Zhuang, Kai Zhou et al.· Analytical Chemistry· 0 citations
Electrocatalytic nitrate reduction (NO3RR) provides a sustainable approach for removing nitrate pollutants and producing valuable nitrogen chemicals. However, understanding catalytic behavior under realistic dilute conditions remains challenging, as conventional electrochemical measurements rely on ensemble-averaged signals that obscure dynamic interfacial processes at individual particles. Here we show an operando electrochemiluminescence (ECL) microscopy strategy that visualizes and evaluates apparent NO3RR kinetics at the single-particle level. Using Cu(111) nanosheets as a model catalyst, we convert reaction-induced optical responses into spatially resolved descriptors of nitrate adsorption and intermediate evolution. The time-dependent ECL response reveals the generation and diffusion of nitrite, a key intermediate in nitrate reduction. These descriptors provide apparent kinetic mapping, uncovering substantial kinetic heterogeneity of individual particles. Correlative imaging of intermediate diffusion demonstrates that interparticle coupling influences apparent catalytic performance by modulating intermediate accumulation and interfacial mass transport under dilute nitrate conditions. This approach provides an operando optical microscopy platform for visualizing dynamic catalytic interfaces and linking interfacial processes with apparent catalytic performance. Understanding catalytic dynamics at electrochemical interfaces is important, while reactions at individual particles remain difficult to observe. Here, the authors report an operando electrochemiluminescence microscopy approach to visualize nitrate reduction processes and monitor apparent kinetics.
