A novel core-satellite CdTe/Silica/Au NCs hybrid sphere as dual-emission ratiometric fluorescent probe for Cu2+.

Herein, we synthesized a novel core-satellite CdTe/Silica/Au NCs hybrid sphere by covalently linking the separately synthesized highly fluorescent bovine serum albumin (BSA) stabilized gold nanoclusters (Au@BSA NCs) to the surface of the amino functionalized CdTe@SiO2 spheres by using the EDC chemistry. Numerous "satellites" of Au NCs were linked on the surface of the CdTe@SiO2 by the way of amide bonding. The synthesized dual-emission hybrid spheres were further characterized by the transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), UV-vis absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy, photoluminescence (PL), etc. Finally, the CdTe/Silica/Au NCs hybrid spheres were developed as ratiometric fluorescence probe for the determination of Cu(2+) with high sensitivity and selectivity. The fluorescence intensity ratio (F545 nm/F655 nm) of the probe against the concentration of Cu(2+) showed a good linear relationship from 6.0×10(-7) mol L(-1) to 100.0×10(-7) mol L(-1). It showed an excellent reproducibility (0.67% relative standard deviation for 10 replicate measurements of Cu(2+) at 40.0×10(-7) mol L(-1)) and low detection limit (4.1×10(-7) mol L(-1)). Furthermore, the ratiometric fluorescent probe was successfully applied in the determination of Cu(2+) in vegetable samples with satisfactory results.