Determination of trace Hg2+ ions based on the fluorescence resonance energy transfer between fluorescent brightener and CdTe quantum dots

The fluorescence resonance energy transfer between fluorescent brightener (FB, donor) and CdTe quantum dots (CdTe QDs, acceptor) was studied and a new method for detecting Hg2+ ions in water samples was accordingly developed in this paper. It was found that the effective energy transfer occurred from FB to CdTe QDs in Tris–HCl buffer solution at pH=8.2, in which the QDs' fluorescence intensity increased greatly. Then the fluorescence quenching occurred as Hg2+ interacted with CdTe. Under the optimized conditions, there was a linear relationship between the fluorescence quenching intensity and the concentration of Hg2+. Hg2+ could be determined in the concentration range of 8.0×10−9–8.0×10−7 g L−1 with a detection limit of 6.6×10−10 g L−1 (S/N=3). The method was applied to the determination of Hg2+ in water samples via the standard addition method, and the recovery rate obtained was 97.3–105.5%. -- Highlights: • Traditional dyestuffs were replaced by the QDs with higher fluorescence yield to establish the energy transfer system. • QDs as acceptor establish a high energy transfer efficiency system to determine the ultra-trace Hg2+. • Energy transfer system based on QDs as an acceptor was applied to detect the Hg2+ ion, was proposed for the first time. • Hg2+ ions detection limit, as low as 6.6×10−10 g L−1 ,is reported, and this system can also be applied in the analytical of real samples