Simple and sensitive detection method for Cobalt(II) in water using CePO4:Tb3+ nanocrystals as fluorescent probes

A simple and sensitive method for detecting cobalt by synchronous fluorescence spectrometry technique with a novel fluorescence probe CePO4:Tb3+ has been developed. CePO4:Tb3+ nanocrystals were synthesized in aqueous solutions and characterized by transmission electron microscopy, electron diffraction pattern spectroscopy and spectrofluorometry. When Delta lambda = 210 nm, the selected synchronous fluorescence is produced at 284 nm. CePO4:Tb3+ nanocrystals were negatively charged under weakly basic conditions (pH = 8.2), which can interact with Co2+ via electrostatic interaction. Moreover, there is the spectrum overlap between the emission wavelength of CePO4:Tb3+ NCs and the absorbance of Co2+. So the energy transfer would occur, leading to the quenching phenomenon. The quenching equation of the system was agreed with the Stern-Volmer equation. The linear range and detection limit of Co2+ were 5-1.8 mu M and 3.5 nM, respectively. The method is successfully applied to the quantification of Co2+ in water samples. (C) 2013 Elsevier B.V. All rights reserved.