Yuting Wang,Jia Liu,Bin Yang,Fengming Zhang,Xin Liu,Shiyue Niu,Shuyun Bi
Based on the fluorescence sensor of 3-Mercaptopropionic acid (MPA) capped CdTe quantum dots (QDs), two novel detection methods for aklomide and nitromide were developed. The MPA-CdTe QDs were synthesized and characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), ultraviolet visible (UV–vis) and fluorescence (FL). The quenchings were all static. The binding constants ( K a ) at different temperatures were obtained. Electrostatic forces were the main forces for the two bindings. For the detection of aklomide and nitromide, under the optimal conditions, the effects of some metal ions, glucose, bovine serum albumin (BSA) and congeneric drug on the determination were explored. The standard equations were established and the limits of detection (LOD) were 0.0215 and 0.0388 μg mL −1 (3 S 0 / S ), repectively. The methods were applied to analyse the samples of chicken and duck, the recoveries were 99.41 % – 101.24 % with RSDs of 0.29 % – 1.19 % ( n = 5).
In this paper, a sensitive Gd 3+ aggregation-induced emission (AIE) fluorescent quantum dots probe for tetracycline detection was designed based on mercaptopropionic acid (MPA)-capped CdTe quantum dots (MPA-CdTe QDs). Gd 3+ can coordinate with the carboxyl groups on the surface of MPA-CdTe QDs, which triggers the aggregation-induced enhancement fluorescence emission effect. Notably, the fluorescence of Gd 3+ -modified MPA-CdTe QDs (Gd 3+ @MPA-CdTe QDs) is quenched by tetracycline (TC). This fluorescent probe exhibits excellent selectivity and sensitivity, achieving the limit of detection of 4.26 nM. Consequently, the MPA-CdTe QDs show an “on-off” fluorescence response. Tetracycline molecule coordinates with Gd 3+ in Gd 3+ @MPA-CdTe QDs, promoting further aggregation of the quantum dots and forming a network structure. Additionally, the inner filter effect (IFE) contributes to fluorescence quenching. The Gd 3+ @MPA-CdTe QDs probe can be applied for detecting TC in milk and tap water, demonstrating significant application potential. Furthermore, Gd 3+ @MPA-CdTe QDs can be utilized for TC detection in living cells.
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