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).
Glutathione-capped water-soluble CuInS/ZnS quantum dots (QDs) were prepared by a microwave-assisted method. Their fluorescence, with excitation/emission peaks at 380/570 nm, is found to be quenched by hydrogen peroxide (H 2 O 2 ) that is produced by the uricase catalyzed oxidation of uric acid (UA) and oxygen. The findings are used in a quenchometric method for the determination of UA. The effects of different ligands on the QDs, of pH value, buffers, enzyme ratio and reaction time were optimized. The detection limit for UA is 50 nM which is lower than other QD-based method, and the detection ranges extends from 0.25–4.0 μM. The assay is simple and sensitive, and no further modification of the QDs is required.
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