Synthesis of Bis-silica-sourced Silicon Quantum Dot Fluorescent Probes for Detection of Cr(Ⅵ)
Cr(Ⅵ)is highly soluble in water,and more than 0.1 mg/L of Cr(Ⅵ)can be toxic to the environment and life and health.Therefore,the exploi tation of a sensitive method for the determination of hexavalent chromium ions is particularly important.Herein,N-[3-(trimethoxysilyl)propyl]ethylenediamine(DAMO)and trimethylsiliconazole(TSIM)were used as the double silicon source precursors,and sodium citrate was used as the reductive agent,and the spherical double silicon source silicon quantum dots(D-SiQDs)were prepared by hydrothermal method.Results showed that D-SiQDs had a spherical structure and a large number of amino and imidazole groups on the surface.Under the optimal conditions,the optimal excitation wavelength of D-SiQDs was 359 nm,and the maximum emission wavelength was 451 nm,and D-SiQDs had good light stability.The fluorescence of D-SiQDs could be selectively quenched by Cr(Ⅵ)and the fluorescence quenching degree as a good linear relationship with the concentration of Cr(Ⅵ)in the range of 0.5-100 μmol/L.The detection limit was 0.056 pmol/L.The recoveries of detecting Cr(Ⅵ)in tap water samples were in the range of 100.37%-105.83%,and the relative standard deviations were all less than 2.36%.Therefore,this paper provides an idea for developing D-SiQDs fluorescent probes for the high-sensitivity detection of Cr(Ⅵ).