Visual detection of fluoride in water by a dual-emitting, Eu-doped Sc-based metal organic framework

Recently, the development of fluorescent sensors to selectively and sensitively detect F− in drinking water has attracted great attention due to the serious harm caused by excessive F− to human bones, kidneys and even DNA. The advantage of a dual emission fluorescent sensor for its fluorescence color change in visualization is well known. In this work, we rationally designed a dual-emitting metal organic framework (MOF) (Eu/Sc)-EBTC, which showed ligand-based emission and Eu3+-based emission and exhibited high selectivity and sensitivity to F− (limit of detection = 16.4 ppb). The sensing mechanism was ascribed to the high affinity between F− and Eu3+ in (Eu/Sc)-EBTC, and was confirmed by PXRD patterns and X-ray photoelectron spectroscopy. Besides, a test strip was made successfully for the practical detection of F−. This study demonstrates the potential of a dual-emission fluorescent MOF sensor for practical applications.