Eosin Y embedded Gd-MOF as a dual emission detection platform for dopamine

A 2D Gd-MOF {Gd-MOF = [Gd(L)(NO3) (DMF)2]n (H2L = 2,5-Bis(1,2,4-triazol-1-yl) terephthalic acid, DMF = N, N-dimethylformamide)} was synthesized based on solvothermal method. To achieve double emission peaks, Eosin Y embedded Gd-MOF (EY@Gd-MOF) was prepared through the synthetic encapsulating method. Due to the effective FRET between EY and Gd-MOF, EY@Gd-MOF shows double emission characteristic peaks. The ratio of emission peaks is used as the detection signal to replace the absolute fluorescence intensity of emission peak, and EY@Gd-MOF as a self-calibrated fluorescence sensor to detect dopamine, which realizes the selective detection of dopamine. Under optimal conditions of pH = 9, dopamine polymerizes to produce polydopamine, which attaches to the surface of EY@Gd-MOF and completely quenches the fluorescence of EY@Gd-MOF and the detection limit for dopamine is 0.124 mu M. Because the excitation spectrum of Gd-MOF fully covers the ultraviolet absorption spectrum of polydopamine, energy competitive absorption is the major cause of fluorescence quenching. In addition, EY@Gd-MOF can be made into a test strip to detect dopamine, and also has the ability to detect in synthetic urine, providing a feasible scheme for the actual detection of dopamine.