Detection Of Antibiotics And Mycotoxins By Surface Plasmon Resonance Effect Of Gold Nanoparticles

Some common precious metal nanostructures,especially gold nanoparticles,have large extinction coefficients and surface plasmon resonance(SPR),which produce significant electromagnetic field enhancements on their surface to enhance the spectral intensity of nearby molecules.The changes in size,distance and morphology will also have different optical properties and macroscopic phenomena.Various detection techniques developed using the SPR effect of gold nanoparticles,such as plasma absorption spectroscopy,surface enhanced Raman spectroscopy,surface plasmon sensors,and plasma imaging,those are widely used in many fields of food safety testing to solve many problems of trace detection.This paper established methods of the SPR absorption detection of neomycin sulfate and surface enhanced Raman scattering(SERS)detection of chlortetracycline and ochratoxin A(OTA)based on the unique surface plasmon resonance effect of AuNPs.These methods are not only simple,fast,but also high sensitivity.The specific research contents are as follows:(1)Establish and optimize the method for detecting neomycin sulfate by Au@PVP nanoparticles.The Au@PVP solution has a surface plasmon resonance(SPR)absorption peak at 542 nm.When neomycin sulfate is added,the hydrogen bonds formed between the amino group of neomycin sulfate and the pyrrolidone oxygen on the shell induce the aggregation of the Au@PVP core-shell nanoparticles,and causing the SPR absorption peak to red shift to 600～700 wavelength region,changing the color of the solution from red to blue.Neomycin sulfate could be qualitativel detected in the range of 10-5～10-7 mol/L by assessing the solution color.Moreover,the intensity of the SPR band at 542 nm decreases as the concentration of neomycin sulfate increases,which can be utilized to quantitatively identify the amount of neomycin sulfate.The linear detection range is 10-5～10-8 mol/Lwith a correlation coefficient of 0.981,and the detection limit is 10-9 mol/L.After extraction with trichloroacetic acid and treatment with hot chloroform,spiked tilapia samples were detected in the linear range of 10-4～10-7mol/L with a detection limit of 2.47×10-7 mol/L.The method has high sensitivity,rapidity,low cost and no complicated pretreatment procedure.(2)Establishing the SERS detection method of chlortetracycline.In this paper,by controlling a certain temperature,selecting the appropriate SERS substrate,optimizing the pH value of the solution,adding a certain amount of strong electrolysis,and repeating drops of gold nanoparticles and sample liquid to achieve the purpose of concentration and enrichment of chlortetracycline,and achieve high sensitivity and reliable SERS quantitative detection of chlortetracycline.The detection linear range of the method is 10-4～10-8 mol/L with the correlation coefficient 0.968,and the detection limit is 2.6～10-10 mol/L.The method was applied to the spiked detection of chlortetracycline in tilapia.The recoveries of the spiked samples were 79.07～86.49%,and the RSD was 1.54～14.57%.This indicates that the method has low detection limits,high sensitivity,high recovery rate for the detection of actual samples.(3)Establishing SERS detection method for OTA based on TGA modified AuNPs.In this paper,thioglycolic acid(TGA)was used to modify AuNPs as SERS substrates,which reduced the surface energy of AuNPs and improved the stability of AuNPs.On the other hand,the free carboxyl groups in TGA molecules formed hydrogen bonds with carbonyl oxygen in OTA molecules.The OTA is pulled into the local electromagnetic field enhancement region of the AuNPs,that is,the SERS hotspot region,and the Raman detection signal is enhanced to realize the highly sensitive SERS quantitative detection of the OTA.The detection range of this method is 2.48×10-5～10-10 mol/L,the linear range is 10-5～10-9 mol/L with the correlation coefficient 0.9846,and the detection limit is 10-10 mol/L.The method was applied to the spike detection of OTA in corn flour.The recoveries of the spiked samples were79.48～106.14%,and the RSD was 2.65～12.72%.It shows that this method has high recovery rate,high detection accuracy and reliable results.