| Surface enhanced Raman spectroscopy（SERS）is a quantitative detection technology based on the scattering effect of the molecules to be measured.However,there are still challenges in the application of SERS,such as sensitivity,reproducibility,repeatability,versatility and long-term stability of SERS substrate.The introduction of metal organic skeleton materials combined with metal nanoparticles can give the substrate the ability to absorb and enrich the target molecules independently,thus binding the detection molecules to the"hot spot"of metal nanoparticles formation,and effectively utilizing the surface plasmon excitation characteristics of metal.This paper is devoted to the preparation of noble metal/metal organic bone frame composite substrate and its application in pollutant analysis.It mainly includes the following contents:1.Determination of glutaraldehyde in water by enhanced Raman spectroscopy based on the surface of metal organic frame composite substrateThe use of glutaraldehyde in fine chemical industry leads to a large number of glutaraldehyde products into the water,which causes serious pollution to the biological and ecological environment of the water body and endangers the whole ecosystem.Therefore,it is essential to develop a rapid and simple detection technique for glutaraldehyde.Surface enhanced Raman spectroscopy（SERS）,an established quantitative detection technique based on the scattering effect of light by the molecules to be measured,offers several advantages such as high sensitivity,low amount of sample required,and small water interference,which is highly functional and widely used in the field of analytical detection.No case has been reported in the literature for the quantitative detection of glutaraldehyde in environmental water bodies based on SERS technology.A surface-enhanced Raman spectroscopy method for the determination of glutaraldehyde in water was developed based on the local surface plasmon resonance effect of gold nanoparticles,the enrichment and concentration of MIL-101（Cr）,and the Schiff base reaction between PATP and glutaraldehyde.Au@MIL-101 was prepared by solution immersion method,and thenthe Au@MIL-101/PATP composite SERS substrate was obtained by modifying PATP on the surface of gold nanoparticles through the Au-S covalent bond.The substrate material is characterized by transmission electron microscope（TEM）,energy dispersive spectroscopy（EDS）,X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）,and Raman spectroscopy.The effect of the density of Au nanoparticles in the composite substrate on the Raman enhancement effect was studied.The Au@MIL-101 material with chloroauric acid concentration at 0.6 g/L has the best enhancement effect.The Schiff base reaction between GA and PATP produces a characteristic peak of C=N at 1621 cm-1.A good linearity between the ratio value of I1078 to I1621 and GA concentration was obtained in the range of 1×10-7～1×10-5mo L/L with the detection limit of 3.5×10-8 mol/L.This method is applied to detect glutaraldehyde in river water and tap water.The recovery rates of standard addition in tap water and river water were 91.4～111.8%,89.8～114.2%,and the relative standard deviations were 5.2～14.5%,8.6～13.4%,respectively.This method has the advantages of simplicity,rapidity,and environmental friendly,which provides a new way for detecting trace glutaraldehyde in water.2.Fabrication of metal organic frameworks silver nanocomposites as SERS substrates for determination of prohibited fishing drugs in fishMalachite green（MG）and crystal violet（CV）are used as therapeutic drugs in aquaculture because of their strong effectiveness in the infection of fungi and parasites in water.However,MG and CV are permanently toxic to mammals due to their genotoxicity and carcinogenic properties and accumulate after entering the food chain.Therefore,MG and CV are banned fish drugs in aquaculture products.We prepared a kind of metal organic frame complex modified by silver nanoparticles（MIL-101-MA@Ag）High sensitivity SERS substrate is used for detection of illegal fishing drugs（malachite green and crystal violet）in tilapia.MIL-101（Cr）with high specific surface area,large pore size,high water stability and solvent stability is used as the supporting material.The surface of MIL-101（Cr）has a large number of unsaturated metal positions,which can be used for surface modification and pore modification in the future.MIL-101（Cr）was prepared by hydrothermal method,and then modified by the functionalization of 3-methylthioaniline to the coordination unsaturated sites of MOFs.Ag NPs was synthesized by ice bath method.The Ag NPs was prepared by simple electrostatic adsorption and Ag-S bond chemical loading Ag NPs MIL-101-MA@Ag Composite basement.It combines the rich Raman"hot spots"and MOFs adsorption properties between high density Ag NPs,and enriches the molecules to be measured and enhanced by their characteristics.The surface load Ag was controlled by the volume of Ag NPs and the incubation time.The density of NPs has achieved the optimization of the material properties.Then,the parameters of detection time,temperature,base concentration and total volume of mixture were optimized by using malachite green as probe molecule.The optimized substrate and detection conditions were used for the detection of malachite green and crystal violet in tilapia fish meat,the detection limits were 9.46×10-11 mol/L and 9.22×10-12 mol/L,respectively.The results show that the substrate has good reproducibility,and the relative standard deviation of MG reproducibility analysis is less than 13.56%.The new SERS substrate can be used for SERS analysis of peacock green and crystal violet in water environment samples and tilapia.The method is simple and effective,and the results are satisfactory.It also lays a foundation for the application of Surface Raman enhanced spectroscopy in the field of food quality and safety. |
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