基于CdTe量子点内滤效应同步荧光猝灭法测定四环素

Synchronous Fluorescence Determination of Tetracycline with CdTe Quantum Dots Based on Inner-filter Effect

以巯基丙酸作为稳定剂制备CdTe量子点,发现CdTe量子点的激发光谱与四环素的吸收光谱有较好重叠,满足发生内滤效应的条件。据此以四环素为吸光体、CdTe量子点为荧光体构建内滤效应荧光传感体系,从而建立一种测定四环素含量的同步荧光猝灭法。实验结果表明,当固定波长差为220 nm时,CdTe量子点的同步荧光最大发射波长为297 nm。在最佳实验条件下,四环素浓度在1.0×10^-6-1.0×10^-5mol·L^-1范围内与体系同步荧光强度呈良好的线性关系,相关系数和检出限分别为0.999和2.5×10^-8mol·L^-1。该方法灵敏度高、选择性好,应用于牛奶样品中四环素的检测,加标回收率为97.0%-104.3%。

The water-soluble CdTe quantum dots（QDs） were synthesized in aqueous solution using 3-mercaptopropionic acid（MPA） as stabilizing agents.It was found that there was an appreciable overlap between excitation spectrum of CdTe QDs and absorption spectrum of tetracycline（TCs）.Thus,the fluorescence inner filter effect（IFE） system was constructed between CdTe QDs（fluorophore） and TCs（absorber）.Based on this IFE system,a synchronous fluorescence quenching method for the determination of TCs was developed.When Δλ was set at 220 nm,the maximum emission wavelength of synchronous fluorescence was 297 nm.Under the optimal conditions,a good linearity was obtained between quenched synchronous fluorescence intensity of CdTe QDs and concentration of TCs in the range of 1.0×10^-6-1.0×10^-5 mol·L^-1.The correlation coefficient was 0.999 and the detection limit was 2.5×10^-8 mol·L^-1.With high sensitivity and good selectivity,the proposed method was successfully applied in the determination of TCs in milk samples with spiked recoveries of 97.0%-104.3%.