Study On Molecularly Imprinted Solid Phase Extraction Column For Guanosine

Molecularly imprinted polymers(MIP)possess the capabilities of recognition of template molecule and its structure analogs.Comparing of nature molecular recognition system such as enzymes,MIP also possess advantages of stability and reusability.Thus,MIP has been extensively used in high performance liquid chromatography(HPLC),solid phase extraction(SPE)and chemical biomimetic sensors.8-hydroxydeoxyguanosine(8-OHdG)is considered to be a marker for oxidative DNA damage,it can be used as a biomarker to diagnose cancer.Therefore,it is great significant to develop molecularly imprinted solid phase extraction column for 8-OHdG.In this thesis,guanosine and ?-methacrylic acid were used as a template and functional monomer,respectively.And both of them were dissolved in a mixture of dodecanol and dimethyl sulfoxide(DMSO),which is used as porogen,together with the cross-linker ethylene glycol dimethacrylate(EDMA),then the initiator azobisisobutyronitile(AIBN)was added.The mixture solution was poured in an empty SPE column and put it in an oven at 45 ? for polymerization.Factors influencing polymerization were discussed and the results showed that the differences between polymerization conditions had fairly influence on adsorption character of the MIP.The final synthesis condition is as following:71.9 mg methacrylic acid,78.8 mg guanosine.1.82 mL dodecanol and 2.32 mL DMSO.Then,the adsorption character of the obtained MIP was investigated by equilibrium adsorption.Adsorption dynamic of guanosine showed that adsorption process reached equilibrium after shook for 12h.Adsorption isotherm showed that the binding curves of the MIP followed the Bi-Langmuir model equation,and two fitting parameters were got with a high affinity site(KD1=0.034?g/mL,Bmax1=0.585?g/mg)and a low affinity site(KD2=2.718?g/mL,Bmax2=0.059?g/mg).Finally the obtained MIP was packed in SPE column for solid phase extraction characterization.Factors influencing its extraction performance,including activating and washing reagents were investigated.The results showed that acetonitrile and H2O as activating reagent,then H2O as washing reagent,is the optimized condition for extraction efficiency.The selectivity experiments showed that guanosine and 2-deoxyguanosine can be condensed selectively.