Recent developments in the preparation, characterization, and applications of chemosensors for environmental pollutants detection

In recent years, chemosensors have been extensively applied to the detection of hazardous materials or envi-ronmental pollutants in various samples because of their excellent sensitivity, wide linear range of sensing, design flexibility, and good anti-interference capability. Organic compound-based chemosensors may contain binding sites or coordination sites for the recognition of specific molecules or ions in food safety checks, as well as agricultural, environmental, and biomedical monitoring. This review article focuses on recent progress in the preparation, characterization, and application of organic molecules or their aggregate nanoparticles as fluores-cent and colorimetric chemosensors for the imaging and recognition of heavy metal ions, anions, amino acids, biothiols, antibiotics, and pesticides in a wide range of biological, agricultural, and environmental samples. Besides, the sensing mechanism, key parameters (chemosensor structure, solvent effect, pH effect) for the sensing performance, and analyzing techniques (solvent polarity, intermolecular interactions, detection limit, binding constant, quantum yield) are also reviewed. Some novel applications, such as on-site seafood freshness tests using smartphones, disposable paper-based sensors, SCN- detection in human saliva of smokers and non-smokers, and explosive sensing, were demonstrated.