Determination of arsenic(iii) based on the fluorescence resonance energy transfer between CdTe QDs and Rhodamine 6G

Abstract

In this paper, a sensitive and selective arsenic(III) (As(III)) detection method based on the fluorescence resonance energy transfer (FRET) system between mercaptopropionic acid (MPA)-capped CdTe quantum dots (QDs) and Rhodamine 6G (R6G) was developed. In this system, CdTe QDs acted as energy donors, while R6G acted as energy acceptor. Glutathione (GSH) could attach to the surface of CdTe QDs to decrease the efficiency of FRET, As(III) could combine with GSH and remove the GSH from QDs, which could recover the efficiency of FRET. We optimized some important factors which would affect the efficiency of the FRET system. Under the optimized experimental conditions, As(III) could be detected based on the fluorescence intensity changes of R6G in the FRET system. There was a good linear relationship between the fluorescence intensity of R6G and the concentration of As(III) in the range of 0.02–2 μmol L⁻¹ and the detection limit was 0.006 μmol L⁻¹. The proposed method has been applied to detect As(III) in lake water samples with satisfactory results.