A novel luminescence-functionalized metal-organic framework nanoflowers electrochemiluminesence sensor via "on-off" system.

A novel solid-state electrochemiluminesence (ECL) "on-off" switch system for highly sensitive detection of tryptophan based on the luminescence-functionalized ruthenium metal-organic framework (Ru-MOF) nanoflowers and CdS quantum dots (CdSQDs) was described. Ru-MOF nanoflowers were prepared by a one-step solvothermal method at low temperature and characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectra and fluorescence (FL) spectra. For potential applications, the Ru-MOF nanoflowers were used to fabricate an ECL "on-off" switch sensor with CdSQDs for the detection of tryptophan enantiomers by quenching effect. Meanwhile the functionalized fullerene nanoparticles were used to enhance signal intensity. Furthermore, the stepwise modified process was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The proposed ECL sensor had a wide linear range from 1.0 nM to 1.0mM with a lower detection limit of 0.33nM for tryptophan enantiomers. This method was simple to prepare, fast to operate, with good sensitivity and excellent stability for the development of efficient and practical ECL sensors.