A novel silicon-C dots based chemiluminescence system and its application for dopamine sensing

Carbon quantum dots (Cdots) are a fascinating class of luminescent nanomaterials that comprise discrete, quasispherical carbon nanoparticles with sizes below 10 nm. They typically display high quantum yield fluorescence with interesting size- and excitation wavelength-dependent behavior [1]. Recently Silicon-Cdots (Si-Cdots), as a new kind of Cdots, have been introduced and attracted considerable interest in various areas [2,3]. In this work, Si-Cdots were prepared by a hydrothermal method and characterized by fluorescence spectra and transmission electron microscopy. The effect of as-prepared Si- Cdots on the very weak CL of HCO3⁻- H2O2 system was investigated. The results showed that Si- Cdots increase the intensity of CL emission and create the second peak in the profile of this system. Moreover, we showed that cationic surfactant, cetyl trimethyl ammonium bromide (CTAB), remarkably enhances the HCO3⁻- H2O2-Si-Cdots CL intensity (about 70-fold). Possible CL mechanisms were elucidated by recording fluorescence and CL spectra. Furthermore, we found that dopamine at even trace levels has a diminishing effect on the CL system. Based on this phenomenon, a new analytical method was developed for the determination of dopamine in the concentration range of 0.1 to 7.5 µmol L-1, with a limit of detection (3s) of 0.075 µmol L-1. The developed method was applied to the determination of dopamine in humen serum samples with satisfactory results.