Synthesis And Applications Of Mercaptopropionic Acid Capped Cd Te@zn S Quantum Dots

Objective:Quantum dots(QDs) have obtained extensive attention interest in recent years because of the broad absorption, narrow emissbn, the size-tunable optical property, high quantum yield, resulting in the expanded application of QDs as fluorescent probe in bio-labeling and fluorescence probe. Comparing with the core quantum dots, the core-shell quantum dots obtained through the coat of inorganic materials have functioned more extensively. Especialy, the toxic QDs coated with non-poisonous material have low toxicity and can be implanted in living body safer with the expanded biomedical values. Methods:To enhance the biocompatibility and obtain more application, Zn S with the property of non-toxic was selected to get water-soluble MPA capped Cd Te@Zn S QDs. The QDs were characterized by Ultraviolet-visible absorption spectrum(UV-Vis), Transmission electron microscope(TEM), Fourier transform infrared spectrum(FT-IR) and fluorescence spectrum. Besides, the fluorescence detection methods were developed.Results:The QDs were successfully characterized, and a fast fluorescence analytical probe for determination of Cu2+ and FA was developed. The detection limit was 1.5×10-9 M and 7.5×10-7 M with the linear range was 0.025-17.5×10-9 M and 0.25-238 μM Conclusions:It was preliminary inferred that the fluorescence quenching way between QDs and Cu2+ was static quenching with the formation of CuxS on the surface of core-shell QDs. The fluorescence probe have higher selectivity for Cu2+ ion over other ions and could be used to detection Cu2+ ion in water with the satisfactory results. However, the fluorescence quenching way was dynamic quenching between folic acid and Cd Te@Zn S QDs. The probe was successfully applied in the determination of folic acid in human body fluids.