Streamlined Synthesis of Ga-Cu Dual Single-Atom Nanozymes for Advanced Electrochemical Sensing Applications

The real-time, rapid, and portable detection of food freshness is crucial for assessing food quality and ensuring food safety. Volatile amines produced during food spoilage have significant potential as markers for evaluating freshness. In this study, an electrochemical sensing platform is developed for the detection of volatile amines using gallium-copper dual single-atom nanozymes (with Ga and Cu contents of 1.31and 4.07 wt.%, respectively) supported by a 2D layered double hydroxide (LDH). The synergistic loading of the dual atoms facilitated binding with volatile amines, which accelerated electron transfer at the GaCu-LDH surface, inducing changes in the electrical signals and enabling detection. The platform exhibited a rapid response time of ≈4 s, with a good linear relationship between the ammonia concentration and steady-state current within the range of 0.05-0.4 mm and a detection limit of 5.9 μm. This electrochemical sensor platform enabled the rapid, portable, and intelligent detection and monitoring of the freshness of meat from livestock and poultry (pork, beef, lamb, and chicken) at room temperature and under refrigerated storage conditions, providing a valuable method for the real-time monitoring of food freshness.