| Mercury(Hg)is a kind of heavy metals having toxicity.Trace amounts of Hg can generate strong toxicity,destroy the cell metabolism and basic functions,and damage the liver function and lead to kidney failure.Its determination at low concentration level is necessary for supporting living organisms,including humans.So the measurement of low concentration levels of mercury and looking for quick and accurate detection method for mercury ion of life activities,including human have the vital significance.Ion selective electrode(ISE)has a lot of advantages,such as fast speed,easy preparation,low cost and high sensitivity.Thus,it has been widely development for mercury ions detection.So it has great application value to design a simple rapid ion selective potentiometric sensor for detection of mercury ion in environment,medicine and agriculture.This thesis mainly discusse thiol self-assembly films on gold electrode for mercury ion recognition.The main contents are as follows:1: We describe a kind of recognition mechanism using electrochemical investigation to probe the sensing mercury ion(Hg2+)in aqueous solutions based on ion selective methods.1-Undecanethiol(1-UDT)is for the purpose of generating self-assembled monolayer(SAM)to recognize Hg2+ on gold surface.The 1-UDT assembled Au electrode(Au/1-UDT)for sensing Hg2+ has a working concentration range of 1.0×10-8–1.0×10-4 mol/L,with a potential response slope of 28.83 ? 0.4 mV/-pC,a detection limit of 4.5×10-9 mol/L,and a good selectivity over the other tested cations.Also,the Au/1-UDT possesses good reproducibility,stability,and short response time.Combined electrochemical analysis with X-ray photoelectron spectroscopy(XPS),the probable recognition mechanism of the electrode for selective recognition of Hg2+ has been investigated.The covalent bond formed between mercury and sulfur is stronger than the one between gold and sulfur and thus prevents the adsorption of 1-UDT molecules on the gold surface.2: A simply gold electrode based on 11-Mercapto-1-undecanol,which was self-assembled on the gold surface,has been developed to wireless sensing recognization for mercury ion.The MUD assembled Au electrode(Au/MUD)for sensing Hg2+ has a working concentration range of 1.0×10-8–1.0×10-3 mol/L,with a potential response slope of 29.96 ? 0.6mV/-pC,a detection limit of 3.94×10-9 mol/L,and a good selectivity over the other tested cations.Also,the Au/MUD electrode possesses good reproducibility,stability,and short response time.Based on these conclusions,the electrode can be used to detecte mercury ions in the living environment.3: By using molecular mechanics,the adsorption of the 1-Undecanethiol(1-UDT)on the Au(110)surface and the mechanism of mercury recognization have been simulated and calculated.From the perspective of the molecular and atomic level,there is a deeper understanding of the nature of the 1-Undecanethiol(1-UDT)on gold electrode surface to form a single molecular self-assembly film,providing more theoretical basis for mercury ion recognition mechanism about the 1-Undecanethiol(1-UDT)modified gold electrode.Using density functional theory(DFT),this paper simulated the 1-Undecanethiol(1-UDT)adsorption behavior on the Au(110)surface,and discussed the 1-Undecanethiol(1-UDT)modified gold electrode for mercury ion recognition mechanism.The stability band structure and charge population analysis of the two different geometric configuration of the reaction product have been discussed.Quantitative calculation results show that mercury and sulfur between strong covalent forces suppressed adsorption of 1-UDT molecules on the surface of the gold electrode,that is,the stronger force between mercury and sulfur between sulfur bond rupture and gold mercury caused by heavy metal.The quantum chemical computation further demonstrates that the strong interaction between the mercury and the sulfur on the gold surface leads to the gold sulfur bond ruptured and gold mercury metallophilic interaction. |
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