Sensitized chemiluminescence of CdTe quantum-dots on Ce(IV)-sulfite and its analytical applications

Water-soluble CdTe quantum-dots (QDs) of different sizes capped with thioglycolic acid (TGA) were synthesized via a microwave-assisted method. It was found that CdTe QDs, as a kind of sensitizer, could enhance the chemiluminescence (CL) emission from the redox reaction of SO3(2-) with Ce(IV) in acidic medium. In combination with the flow injection technique, the effects of reactant concentrations, the sizes of CdTe QDs, some organic compounds, and several electron transfer proteins on the CL emission were investigated in detail. The sensitized CL displayed the size-dependent effect and increased along with increasing the QDs sizes. Organic compounds containing OH, NH2, or SH groups, and some electron transfer proteins such as cytochrome c, hemoglobin and myoglobin, which readily interact with CdTe QDs, were observed to inhibit the CL signal of the Ce(IV)-SO3(2-)-CdTe QDs system, which made it applicable for the determination of such compounds and proteins. The CL enhancement mechanism was also discussed briefly on the basis of the photoluminescence (PL) and CL spectra. This work is not only of importance for gaining a better understanding of the unique optical and physical chemistry properties of semiconductor nanocrystals but also of great potential to find applications in many fields such as luminescence devices, bioanalysis, and multicolor labeling probes.