A rapid and specific fluorescent probe based on ESIPT-AIE-active for copper ion quantitative detection in food and...

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.