Quantum Dots Enhance Luminol Chemiluminescence To Determine Phenolic Compounds In Environment

With the remarkable size-dependent optical and electronic properties, quantum dots have been applied in the catalysis, the nonlinear optics, the magnetic material, the solar energy transform and so on. Flow injection chemiluminescence (CL) technique is used for highly sensitive of trace and half trace substance analysis. It has been intensively investigated for many years in analytical chemistry area. In this paper, three quantum dots were synthesized and added to different luminol CL system, respectively. New CL system were founded and used for determine phenolic compounds in environments. The main contents were described as follows:(1)Thioglycolic acid (TGA) capped CdTe QDs were synthesized via the hydrothermal route. CdTe QDs could strongly enhance the luminol-H2O2CL system in alkaline medium. So a new CL system that luminol-H2O2-CdTe QDs was founded. Based on the phenomenon that hydroquinone could strongly inhibit this new CL system, a simple and sensitive method for the determination of hydroquinone was developed. The linear range for the determination of hydroquinone was1.0×10-9～2.5×10-8mol/L, the limit of detection of7.6×lO-10mol/L, the relative standard deviation of2.6%for11solutions of4.0×10-9mol/L hydroquinone on the same day. The method was applied to determine hydroquinone in some water samples and satisfactory results were obtained. Furthermore, the possible enhancement mechanism of CdTe QDs on luminol-H2O2CL system was discussed briefly on the basis of the UV-Vis absorption spectra and fluorescence spectra.(2) TGA-capped CdTe/CdS QDs were synthesized via the hydrothermal route. Based on the phenomenon that hydroquinone can obviously inhibit the CL signal of the luminol-potassium ferricyanide system catalyzed by CdTe/CdS QDs in basic medium, a simple, rapid and sensitive method for the determination of hydroquinone has been developed. The linear range for the determination of hydroquinone was7.0×10-10～4.0×10-7mol/L, the detection limit of3.2x10-10mol/L. the relative standard deviation of2.5%for11solutions of1.0×10-8mol/L hydroquinone on the same day. This method was applied to determine hydroquinone in some water samples and satisfactory results were obtained. Furthermore, the possible enhancement mechanism of CdTe/CdS QDs on luminol-potassium ferricyanide CL was further investigated based on the UV-Vis absorption spectra and fluorescence spectra.(3)Glutathione-capped ZnSe QDs were synthesized via the hydrothermal route. Based on the phenomenon that2,4,6-trichlorophenol can inhibit the CL signal of the luminol-KMnO4system catalyzed by ZnSe QDs in alkaline medium, a simple, rapid and sensitive flow-injection chemiluminescence method for the determination of2,4,6-trichlorophenol has been developed. The linear range for the determination of hydroquinone was4.0×10-9-1.0×10-7mol/L,the detection limit of4.0x10-10mol/L, the relative standard deviation of1.5%for11solutions of1.Oxl0-8mol L-12,4,6-trichlorophenol on the same day. The method was applied to determine2,4,6-trichlorophenol in some water samples and satisfactory results were obtained. Furthermore, the possible enhancement mechanism of ZnSe QDs on luminol-KMnO4CL was further investigated based on the UV-Vis absorption spectra and fluorescence spectra.