基于CdTe/ZnS量子点共振能量转移荧光猝灭法测定孔雀石绿

Determination of Malachite Green by Fluorescence Resonance Energy Transfer Quenching Method Based on CdTe/ZnS Dots

以巯基乙酸作为稳定剂合成了CdTe/ZnS量子点,发现CdTe/ZnS量子点的荧光发射光谱与孔雀石绿的吸收光谱能有效重叠,且该量子点与孔雀石绿能通过静电吸引力结合,满足荧光共振能量转移的条件,据此建立了以CdTe/ZnS量子点为供体,孔雀石绿为受体的共振能量转移体系,并将该体系用于孔雀石绿含量的测定。研究发现,在pH 8.0的Tris-HCl缓冲溶液中,当量子点的浓度为1.6×10-4mol/L时,体系的荧光猝灭程度与孔雀石绿的浓度呈良好的线性关系,线性范围为0.048～3.2μmol/L,相关系数为0.999 3,方法的检出限为0.015 8μmol/L,该方法已成功用于实际水样的测定,加标回收率为99.3%～102%。并对CdTe/ZnS量子点与孔雀石绿之间的反应机理进行了讨论。

The water-soluble CdTe /ZnS core-shell quantum dots（QDs） were synthesized using thioglycolic acid（TGA） as stabilizer.It was found there is an appreciable over lap between the emission spectrum of CdTe /ZnS QDs and the absorption spectrum of malachite green（MG）.Moreover,the interaction（mainly the electrostatic force） between the electronegative CdTe QDs and cation dye MG can draw them close.Thus,the fluorescence resonance energy transfer（FRET） system was constructed between CdTe /ZnS QDs（donor） and MG（acceptor）.Based on this FRET system,a sensitive method for the determination of MG was developed.Effects of experimental conditions were investigated.The optimal conditions were as follows：buffer：pH 8.0 Tris-HCl solution,concentration of quantum dots：1.6×10-4 mol/L,reaction time：20 min,reaction temperature：30 ℃.Under the optimal conditions,a good linearity was obtained between the quenched fluorescence intensity of CdTe /ZnS QDs and concentration of MG in the range of 0.048-3.2 μmol/L.The correlation coefficient was 0.999 3 and the limit of detection（3σ） was 0.015 8 μmol/L.The proposed method was successfully applied in the determination of MG in water samples with spiked recoveries of 99.3%-102 %.Furthermore,the possible mechanism of interaction between CdTe/ZnS QDs and MG was discussed.