“…1,2 Many Cu 2+ assays have been developed based on organic fluorescence 3,4 , chromogenic sensors 5,6 , quantum dots 7-9 , nanoparticles 10 , and atomic absorption spectroscopy 11,12 . However, many of these methods require sophisticated equipment, are time consuming, or have low sensitivity. Excess copper ions in the air, water and soil can also cause heavy metal contamination via food chain and biological aggregation, which can seriously affect wildlife and ecological systems.…”