Nanjing University of Finance & Economics

In the field of food safety, the identification and measurement of active components in food is a pressing issue. The concentration of copper ions (Cu²⁺) in the environment is closely linked to food safety, and overall biological health. Therefore, developing rapid and accurate analytical techniques to monitor Cu²⁺ in food is of great significance. In this study, two fluorescent probes L-2 and L-3 were synthesized through a simple Schiff base condensation reaction. And L-3 demonstrated better anti-interference ability to Cu²⁺ than that of L-2. Meanwhile, spectroscopic experiments showed that L-3 possessed an extremely low detection limit (LOD) and low limits of quantification (LOQ) (LOD = 92.79 nM, LOQ = 309.33 nM), and quickly respond time (<30 s). Probe L-3 for monitoring effectively quantitatively identified Cu²⁺ in food and environmental samples, achieving an accuracy rate ranging from 84.42% to 117.45% and precision with a relative standard deviation (RSD) of less than 6.0%. The accuracy had been validated using the inductively coupled plasma-mass spectrometry (ICP-MS). Simultaneously, a WeChat Mini Program has been developed to detect total copper content in food samples based on fluorescence values, enabling consumers to evaluate food safety more intuitively. Moreover, L-3 also facilitated the quantitative visualization of Cu²⁺ in biological systems, underscoring its compatibility and practicality.

This study combined reactive molecular dynamics (RMD) simulation with experimental verification to investigate the degradation of deoxynivalenol (DON) in wheat grains by sodium bicarbonate assisted cold plasma (SB-CP). The results showed that SB-CP treatment increased the degradation rate of DON from 52.88 % to 80.54 % and effectively improved the quality of wheat. The RMD simulation and reactive particles measurements confirmed that the increase in the degradation rate was due to SB promoting more reactive particles. By combining the five degradation products identified by LC-MS with the possible intermediate products obtained from the simulation, and based on the ease of formation and cleavage of chemical bonds in the DON molecule by reactive particles, the specific formation pathways of these products and the mechanisms of each reaction site were revealed, mainly involving the C9C10 double bond, the C12-C13 epoxy ring, and hydroxyl groups.

The development of innovative materials for selective lead (Pb) capture is crucial, but regeneration research is insufficient, particularly regarding regeneration without chemical reagents. Herein, we introduce a smart, thermally regenerable MOF-based adsorbent for Pb^2 + by incorporating poly(N-isopropylacrylamide) (pNIPAM) and benzo-18-crown-6 ether (B18C6) into MOF-808 (MOF-808-pNB). MOF-808-pNB could capture Pb²⁺ with remarkable removal efficiency (> 99.7 %), ultrafast kinetics (k₂ ∼ 14.95 g mg^-1 min^-1), and outstanding selectivity (K_d > 1.6 × 10⁶ mL g^-1) in multi-ion mixed solutions (e.g., Li⁺, Ca²⁺, Ba²⁺, Cu²⁺, Ni²⁺). Importantly, this material could be easily regenerated at 45°C, showing excellent recyclability (Pb²⁺ adsorption and desorption ∼ 99 % after 10 cycles). Column experiments demonstrated that 1 kg material could treat 3250 L of authentic Pb-contained wastewater to meet drinking water standards (Pb < 0.01 mg/L). Mechanism studies indicate that B18C6 within the material acts as a specific site for capturing Pb²⁺ at 25°C, whereas pNIPAM shrinks thermoresponsively to a hydrophobic state at 45°C. These alterations introduce steric hindrance and repulsion, combined with exothermic properties of B18C6, collectively enabling efficient Pb²⁺ desorption. This work highlights the potential of thermoresponsive MOF-808-pNB for Pb²⁺ removal and provides a reference for the design of stimuli-responsive materials aimed at water purification.