Research On Specific Detection Technology Of Mercury Ion Based On SPR And Self-assembly Technology

In this paper,SPR（Surface Plasmon Resonance）technology is combined with chemical self-assembly technology,and chemical substances that have a specific adsorption effect on mercury ions are used to modify them on the sensor chip to realize the effect of SPR technology on mercury ions.Selective detection.This method has the advantages of no need to label the analyte,high sensitivity and fast detection speed.In terms of principle,this thesis first derives the concepts of surface plasmon wave and attenuated total emission at the theoretical level,and finally obtains the conditions for SPR excitation.Secondly,the detection principles of sensors based on SPR technology are introduced respectively;the principle of 1,6-hexanedithiol chemical self-assembly onto gold film and the principle of 1,6-hexanedithiol selective detection of mercury ions.In the simulation stage,first introduced the SPR theoretical simulation system based on Kretschmann structure.Secondly,this paper simulates the four-layer Kretschmann structure through the system,and explains the core algorithm of the system—the transition matrix method.Then,according to the system,the metal film parameters in the Kretschmann structure were simulated by angle modulation,and the effects of Ag and Au materials on the SPR performance were compared respectively,and the Ag/Au composite film structure was determined.For stability on the substrate,a Cr film is added between the metal film and the substrate.In the end,the best results of each film are:Cr film 1 nanometer,Ag film 40nanometers,and Au film 5 nanometers.In the experimental stage,first introduced the Kretschmann structure of the SPR experimental platform built in the laboratory,and then introduced the solution configuration process,the required reagents,the preparation of the chip,the modification of1,6-hexanedithiol,and the experimental operation steps.Then,the self-assembly modification experiment of 1,6-hexanedithiol was carried out;the modified SPR sensor’s detection experiment of single mercury ion;the modified SPR sensor’s selective experiment of mercury ion in the mixed solution;the modification substance to SPR Experiment on the influence of sensor sensitivity.Finally,the addition of the modified substance causes the resonance angle to shift by 0.15°.The detection limit of the modified sensor for a single mercury ion solution is 240nmol/L,and the sensitivity is 1.25×10^-2°/mg/L.The response of mercury ions in the mixed solution is 0.8°,and the response to other ions is 0.2°.The detection limit of the unmodified chip for a single mercury ion is 5.7mol/L,and the sensitivity is 5.3×10^-4°/mg/L.Compared with the unmodified chip modified,its sensitivity increased by two orders of magnitude.These experimental results show that the SPR sensor modified with1,6-hexanedithiol can achieve specific detection of mercury ions.