Combine Surface Enhanced Raman Scattering Combine With Molecular Imprinting To Detect PEDs

The increasingly serious problem of environmental pollution has been growing attention with the development of the global economy and technology, especially the phenolic endocrine disruptors (PEDs), which is causing the human ecological environment deterioration and the sharp decline of biodiversity. PEDs are very widely distributed in the environment and have a very low concentration, which is difficult to be detected, so the development of rapid, high sensitivity, economic and efficient detection method is particularly urgent. Surface enhanced Raman scattering (SERS) has been widely used in the detection of pollutants in the environment because of its rapid detection, high sensitivity, and simple pretreatment in recent years. But the substrate of the SERS is not stable and has no specific selection susceptible to interference from other impurities in the environment, that can affect the accuracy and sensitivity of the test results. Molecular imprinting technology (MIT) can make up for the lack of SERS as a kind of special separation and adsorption technology, making SERS defects of can’t select specificity have been effectively resolved. Molecular imprinting technology (MIT) can make up for the lack of SERS as a kind of special separation and adsorption technology, making SERS defects of can’t select specificity have been effectively resolved. Using the specific recognition ability of molecularly imprinted polymers (MIPs) can not only improve the detection sensitivity of SERS, but also can avoid the interference of other pollutants. Combining SRES technology with MIT technology provides a new way for the detection of trace concentrations of pollutants.This article will combine SRES with MIT and prepare a kind of imprinted microspheres Ag-MIPs, which prepared with silver particles as a core, surface molecularly imprinted polymer as shell. The silver particles were prepared by the reduction of ascorbic acid and sodium citrate. With silver particles as SERS active substrate and octylphenol (OP) as a probe to measure the SERS signal enhancement. Result shows that sodium citrate reduction of silver nanoparticles is more suitable as a silver core of molecularly imprinted microspheres. Ag@SiO2 particles were prepared with 7nm,15nm,25nm,35nm,50nm coating thickness through the hydrolysis of tetraethoxysilane (TEOS) deposited SiO2 on the surface of silver particles. With OP as the probe measured SERS effect with a variety factor of OP concentration, shell thickness and concentration of Ag@SO2, and measured OP of the minimum detection limit is 1μg/L. The silica gel surface molecular imprinting technique was used to successfully prepare with a specific adsorption of MIPs with obtained silica gel particles by the hydrolysis of TEOS as the carrier, APTES as functional monomer and OP as the template molecule. To specific adsorption of octylphenol by MIPs, it is concluded that MIPs reach adsorption equilibrium state after 60 min in dynamics, in which case the maximum adsorption reached MIPs was 33.465μmol/g. Using Ag@SiO2 particles as the carrier, APTES as functional monomer, octyl phenol as the template molecule to prepare a layer of molecularly imprinted membrane on the surface of silver particles, and it was successfully prepared core-shell type molecularly imprinted microspheres Ag-MIPs. Though Ag, Ag@SiO2 and Ag-MIPs particles of SERS active contrast with OP as the probe, shows that the SERS enhancement effect of Ag-MIPs particles is strongest and measured OP of the minimum detection limit is 10-12 mmol/L. It indicate that the outer layer of the Ag-MIPs molecularly imprinted membrane had specific adsorption, which make the trace of OP be enriched on the surface Ag-MIPs particle and enhance the SERS signal. It is fully proved the feasibility of the combined of MIT and SERS technique. Imprinted microspheres Ag-MIPs successfully combine MIT with SERS technology to make the advantages of both plays together, which provide a high sensitivity and specificity adsorption of trace detection technology and a new detection channels for the analysis of material.