The Study Of Synthesis Of Gold Nanoparticles And Their Application In The Detecting Hg²⁺

With the development of analytical technologies and the introduction of interdisciplinary,fluorescence analysis method due to high sensitivity,selectivity and simple operation has been widely used in the fields such as environmental,biological molecular,drug analysis,and food security.In this thesis,We researched several kinds of gold nanoparticles with different surface ligands,discussed their special properties in optics,and applied to the detection of heavy metals in water particles based on the quenching of fluorescence owing to the interaction between gold nanoparticles and heavy metal particles.The contents of the paper are as follow:The synthesis of uniform and reliable luminescent gold nanoparticles was carried out by the chemical reduction of HAuCl4 with mercaptosuccinic acid as the reductant and stabilizers.The800 nm emitting AuNPs with single size which have great water-solubility was synthesized with a reflux condensation method at 95^oC for 45 hours.Nanoparticle fluorescence quantum yield is0.4%calculated with Nile Blue as the reference.In this thesis,the effect of reaction ratio,reaction time and reaction temperature on the synthesis of gold nanoparticles were also investigated.The proposed methods were applied to the detection of heavy metal ions in water samples and provided new ideas.The fluorescence quenching of gold nanoparticles result from the strongly interaction between Hg²⁺and Au+from gold nanoparticles.And the degree of fluorescence quenching is proportional to the concentration of mercury ions.Based on this,we detected the concentration of mercury ion in the solution according to the changes of the fluorescence intensity of gold nanoparticles,and developed a detection method for trace mercury ion.The dynamic concentration range spanned from 10 nM to 4 uM and the detection limit 4.8 nM?S/N=3?.Secondly,the Cys-AuNCs was synthesized through the reduction of chloroauric acid and cysteine at room temperature.The average diameter of the plate-shaped Au NCs is 75nm.The self-assembly mechanism was investigated.A good linear relationship between fluorescence intensity with mercury ion concentration due to Hg²⁺and Au⁺from gold nanoparticles has been found.Based on this,we developed a detection method mercury ion in water with the fluorescence intensity of gold nanoparticles.The dynamic concentration range spanned from 2 nM to 50 uM.