Construction Of Surface Plasmon Resonance Biosensor And Application To Rapidly Detect Pesticides

In recent years, with the development of urban and rural economy, our living level isbeing raised, and we have a growing number of food. Pesticides have been extensive used forimproving the output of agricultural products which lead to the severe problem of pesticideresidues. Excessive pesticide residues seriously influence people’s health and ecologicalenvironment security. Therefore, developing rapid, simple and sensitive analysis forpesticides residues has an important significance.The detection technology of Surface Plasmon Resonance （SPR） is a kind of physicaloptics phenomenon which originates from the metal film optical coupling. The SPR techniquecan realize real-time monitoring molecule interactions without labeling, separation andpurification of samples. And it can determine the type and concentration of reactant.Furthermore, it has been widely used in various fields for its small sample volume, highsensitivity, rapid detection and other advantages.In this work, we choose the Fourier Transform-Surface Plasmon Resonance （FT-SPR） asthe main analytical tools. And basing on the principle of FT-SPR, we constructed two kinds ofFT-SPR sensor chips which could monitor the analysis of relevant pesticides.1. AChE was applied in SPR biosensor for organ phosphorus pesticides detection. AChEwas immobilized on the sensor chip basing on the modified membrane of3-mercaptopropionic acid （MPA） which was used to modify the sensor chip by molecularself-assembly technique. The sensor chip realized the detection of dichlorvos through theinteraction between AChE and dichlorvos. Different concentrations of dichlorvos solutionwere poured into the SPR flow cell by gradient concentration, and the response signals wererecorded when the solution of dichlorvos flowed through. When the concentration ofdichlorvos is low, the SPR wavenumber shift is very small and not stable. However, the SPRwavenumber shift was obvious as the concentration of dichlorvos solution increased.Linearregression analysis between concentrations of dichlorvos and the corresponding SPRwavenumber shifts was carried on in the range of20¹00mg/L dichlorvos, and preferablelinear equation of curve y=2.014+0.07535x,（R=0.99847） was obtained. The results showed that FT-SPR biosensor based on AChE can be used for detecting dichlorvos.2. Mercapto-β-Cyclodextrin （SH-β-CD） was applied in SPR sensor for atrazine detection.β-Cyclodextrin was directly immobilized on the surface of FT-SPR sensor chip through thebinding between thiol group and gold nanoparticles which plated on the chip surface. Thissensor could detect atrazine through the peculiar hydrophobic cavum of β-Cyclodextrin whichcould form inclusion complexes with various guests molecular. FT-SPR wavenumber shiftchange in different degrees when various concentrations of atrazine solution were flowed intothe SPR flow cell. Linearregression analysis between concentrations of atrazine and thecorresponding SPR wavenumber shifts was carried on in the range of80×10^-81250×10^-8mol/L mol/L atrazine, and preferable linear equation of curve y=0.01586x+5.48804,（R=0.9948） was obtained. This result showed that the FT-SPR sensor using SH-β-CDmodification can be used for detecting atrazine.