Preparation Of Gold Nanoclusters And Application Research On Mercury Ion Detection

Gold nanoparticles have drawn a lot attention by researchers,due to the advantages of simple preparation method,stable chemical property,good biocompatibility and easy surface modification.When the size of gold nanoparticles is gradually reduced to the Feimi wavelength,its electronic structure is similar to that of the semiconductor.These ultra-small gold nanoparticles,also known as gold nanoclusters(Au NCs),have detected many target analytes based on its excellent optical properties,such as long fluorescence lifetime,large Stokes shift and tunable emission wavelength,and the detection technology is very mature.However,there are still few researches on the biomimetic enzymes.In this paper,we studied the peroxidase-like activity of Au NCs and established a spectrophotometric method for the detection of heavy metal ions of Hg2+ in lake water.The main research contents are as follows:1?Au NCs were prepared by chemical reduction method,using HAuC14 as precursor and glutathione(GSH)as reducing agent and stabilizer.The properties,morphology,and structure of the prepared materials were characterized by UV-vis,transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS).2?In buffer solution,GSH-stabilized Au NCs had high peroxidase-like activity and could catalyze the oxidation of the peroxidase substrate 3,3',5,5'-tetramethybenzidine(TMB)in the presence of H2O2 to generate a blue color sugnal,however,when Hg2+ was introduced to the system,the peroxidase-like activity of the Au NCs was inhibited,leading to a blue color fading.Utilizing this importment phenomenon,a simple and rapid Hg2+ sensor was established.In order to detect Hg2+more effectively,sensing conditions,including pH of buffer solution,TMB concentration,H2O2 concentration,were optimized.Selective and interference experiments were performed to ensure the high selectivity of the probe.The results showed that the Hg2+ probe had a high selectivity.3?We evaluated the detection sensitivity of the proposed method.The results showed that the calibration curve was constructed between the change of absorbance(A0-A)of the system and the concentration of Hg2+.In order to verify the practicability of the established method,the Au NCs system was used to detect Hg2+in lake water.