Synthesis Of CdTe/znS Core-Shell Quantum Dots And Interaction With Cetirizinehydrochloride

Quantum dots（QDs） is also known as semiconductor nanocrystal, the size ofwhich is always within10nm. It is composed of IIIB-VB or IIB-VIB race elements.QDs shows many unique optical and physical chemical characteristics: strong andstable fluorescence intensity, high quantum yields, strong anti-photobleaching ability,anti-chemical degradation, broad excitation spectrum, narrow and tunable emissionspectrum, larger stokes shift. In recent years, as a fluorescence probe, QDs has drawnmore and more attentions in the field of biology and biomedical applications.In this pape, CdTe/ZnS core-shell QDs has been prepared by injecting Zn²⁺（aq）simply into an CdTe/ZnS core-shell QDs with an average diameter of3.37nm, whichwere synthesized and stabilized with assistance of3-mercaptopropionic acid by anaqueous approach, moreover, the property and the structure of CdTe/ZnS core-shellQDs were characterized.UV-vis spectrum absorption edge method was used to estimate the size of QDs.The X-ray diffraction of powders indicates furtherly that QDs was consisted of acore-shell structure, rather than an alloyed structure. Taking ethanol solution ofrhodamine B was as a reference object, the quantum yield of CdTe/ZnS core-shellQDs was calculated to be59%.Interaction of CdTe/ZnS core-shell QDs and cetirizinehydrochloride was studiedby fluorescence spectrum and UV-vis absorption spectrum.The optimum reactionconditions was found to be at pH7.1in phosphate buffer solution. when the denesityof CdTe/ZnS core-shell QDs is3.33×10^－5mol/L, the quenched fluorescence intensityof CdTe/ZnS core-shell QDs was linearly proportional to the denesity ofCetirizineHydrochloride from1.7×10^－6to2.33×10^－5mol/L, with the correlationcoefficient r being0.9916, and LOD=2.32×10^-7mol/L. Both of dynamic quenchingand static quenching can exist at the same time in the fluorescence quenchingexperiment. The combination of CdTe/ZnS core-shell QDs andcetirizinehydrochloride happens when ΔG<0, ΔS>0. This is an irreversible and spontaneous process, since the entropy increased and the Gibbs free energy decreased.The amounts of cetirizinehydrochloride in pill were determined with the proposedmethod, and the results agreed with the claimed value with the recovery of96.2-99.6%.