Thioglycerol-functionalized CdSe quantum dots detecting cadmium ions

Nassim Ben Brahim (1) , Naim Bel Haj Mohamed (1) , Mosaab Echabaane (1) , Mohamed Haouari (1) , Rafik Ben Chaâbane (1) , Michel Negrerie (2) , Hafedh Ben Ouada (1)

1 FSM - Faculté des Sciences de Monastir
2 LOB - Laboratoire d'Optique et Biosciences

Water-soluble CdSe quantum dots (QDs) were synthesized using thioglycerol (TG) as the surface capping agent through a one-step process at low temperature T (100 degrees C). The CdSe quantum dots were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, UV-visible absorption and fluorescence spectroscopies. These measurements revealed that the TG-capped CdSe QDs possess a high crystalline quality with an average diameter in the range 2.5-2.8 nm and exhibit particular optical properties. The UV-visible absorption of CdSe QDs is enhanced by the addition of cadmium ions, with a simultaneous shift of the edge band (400 nm), while seventeen other tested metal cations have no effect on the absorption of QDs. Moreover, the binding of Cd2+ ions induces a quenching of the fluorescence emission of TG-CdSe QDs. At particular absorption wavelengths, the response is linearly proportional to the cadmium ions concentration ranging from 1.0 to 22 mu M with a detection limit of 0.32 mu M (37 mu g L-1). Based on these optical properties, the TG-CdSe QDs could be used as a highly selective probe for the detection of Cd2+ ions in aqueous solutions, a species highly toxic for cells. (C) 2015 Elsevier B.V. All rights reserved.

Domaines: Optique [physics.optics]

Nassim Ben Brahim, Naim Bel Haj Mohamed, Mosaab Echabaane, Mohamed Haouari, Rafik Ben Chaâbane, et al.. Thioglycerol-functionalized CdSe quantum dots detecting cadmium ions. Sensors and Actuators B: Chemical, 2015, 220, pp.1346-1353. ⟨10.1016/j.snb.2015.07.049⟩. ⟨hal-01222839⟩