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%.