Abstract
A turn on fluorescent sensor based on 2-[4-( 2-aminoethylthio) butylthio]ethanamine ionophore and [5]helicene fluorophores, MC4 was developed for detection of Ag+. An aqueous ethanol solution, an environmental friendly condition, was chosen as a working condition. MC4 exhibited Ag+-induced fluorescent enhancement with a low detection limit of 32 ppb for Ag+. The detection limit of the sensor was below the permissible concentrations of Ag+ for drinking water as regulated by the United States Environmental Protection Agency (U.S. EPA) and World Health Organization (WHO). Moreover, MC4 exhibited a strong fluorescent signal and expansive stokes shift of 213 nm. This very expansive stokes shift could reduce interferences from self-absorption and auto-fluorescence. The sensor also provided highly selective recognition of Ag+, distinguishing it from other competing ions through the photoinduced electron transfer (PET). Importantly, this sensor is able to track Ag+ in HepG2 cells, indicating that it shows good potential for practical applications.
