Detection of melamine based on the fluorescence resonance energy transfer between CdTe QDs and Rhodamine B.

In this paper, we constructed the fluorescence resonance energy transfer (FRET) system between MPA-capped CdTe quantum dots (QDs) and Rhodamine B (RB) in the environment of cetyltrimethylammonium bromide (CTAB). In this system, CdTe QDs were treated as energy donors, whilst RB was treated as energy acceptor. CTAB was used to make the distance between the particles of CdTe QDs and RB closer to improve the efficiency of FRET system. We optimized some important factors which would affect the efficiency of FRET system. Under the optimized experimental conditions, melamine (MB) could be detected based on the fluorescence intensity changes of RB in the FRET system. We could get a linear relationship between the fluorescence intensity of RB and the concentration of MB in the range of 0.05-4.0 μmol/L and the detection limit was 0.01 μmol/L. The proposed method was applied for the determination of melamine in milk samples with satisfactory results.