A comprehensive review on recent advances in copper sensors

Copper (Cu2+) exists in nature and biological systems and therefore its detection in soil, blood, urine, water, agriculture and food samples is of great significance. Attempts to develop colorimetric and fluorimetric sensors for the detection of Cu2+ have picked up the pace in the last several years. Three types of Cu2+ sensors (chemical, polymer and nanoparticle) are reported based on (i) colorimetric, (ii) fluorimetric and (iii) colorimetric and fluorimetric dual criteria. The present review intends to give a description of these reports published between 2015 and 2021 with emphasis on absorption and emission parameters of Cu2+ binding, sensing mechanisms, structures and their applications.