| In recent years, colloidal semiconductor nanocrystals or quantum dots (QDs) have attracted much attention due to their unique size dependent optical and electronic properties. However, the heavy metal Cd2+QDs stabilized by hydrophobic capping molecules are disadvantageous in applications requiring water soluble and nontoxic QDs, such as biologic applications. ZnSe QDs show great potential applications due to their low cytotoxicity which have attracted significant amount of interests. However, the applications of ZnSe QDs in analytic chemistry are lack of research.Enviromenal hormone pollutants widely exist in the environment we lived, which would pose a threat to the sustaind living and proliferation of humans and anaimals. Therefore, an increasing attention has been paid to the research and development of new analytical methods with sensitivity, selectivity, simplicity and applicability. In this paper, we have used ZnSe QDs in chemiluminescence and electrochemistry to determine some environmental hormones:(1)Water-soluble ZnSe QDs capped with Glutathione (GSH) was synthesized. With the Zn(Ac)2as Zn sourse and glutathione as the stabilizer, we demonstrate a novel method of direct synthesis of water-soluble and low toxic ZnSe QDs in aqueous media. The results of absorption and fluorescence spectra, transmission electron microscopy and X-ray diffraction demonstrated the small particle size, good monodispersity and ZnSe alloyed structure of as-prepared QDs.(2) It was found that ZnSe QDs could enhance the chemiluminescence (CL) emission from the luminol-K3Fe(CN)6system in alkaline medium, and the enhancement mechanism of ZnSe QDs on luminol CL was discussed. What’s more, we found that the CL from luminol-K3Fe(CN)6-ZnSe QDs system is strongly inhibited by the presence of phenols. Based on this inhibition, a novel CL method with a lower detection limit and wider linear range was developed for the determination of three kinds of phenol in tap water samples and diethylstilbestrol in milk samples. The limits of detection were in the range of8.0×10-1.0-8.0×10-9mol/L and the relative standard deviation (RSD) were in the range of1.1-1.6%.(3) A simply electrochemical method based on ZnSe/MWNTs/DMF/GCE was developed to determine pentachlorophenol (PCP) using cyclic voltammetry and differential pulse voltammetry. The PCP showed a well-defined oxidation peak at the fabricated electrode in phosphate buffer solution and the oxidation peak current is much higher than that at the bare GC electrode. Several effect factors on PCP determination were optimized. Under the optimal conditions, the oxidation peak current of PCP was proportional to its concentration in the range of8.0×10-8to4.0×10-6mol/L with a correlation coefficient of0.9969, respectively. The limit of detection was estimated to be2.0×10-9mol/L. The developed method showed good reproducibility and excellent selectivity. The fabricated electrode was successfully used to determine PCP in tap water and lake water samples with acceptable recovery.(4)A ZnSe/MWNTs/Nafion/GCE was prepared. The complex was characterized by transmission electron microscopy (TEM). It was found that estriol yield one well-defined oxidation peak at the ZnSe/MWNTs/Nafion/GCE. The peak current is proportional to the concentration of estriol in the range from8.0x10-7to3.0×10-5mol/L, and the detection limit is6.0×10-8mol L-1. The RSD of five measurements is2.3%for2.0×10-5mol L-1estriol. The method described is simple, sensitive, and has been successfully utilized for the determination of estriol in serum samples. |
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