| Phytohormones are a collection of naturally engendered molecules which play key role in regulating physiological processes in plants,including cell proliferation and differentiation,seed germination,organ formation,stem elongation,senescence,etc.It’s significant to understand how the phytohormones regulate the formation of important organs and shapes in plants.So quantitative analysis of phytohormones is necessary in depth study of crop yield,quality regulation and breeding innovation,etc.However,the analysis of phytohormones in plants is a difficult task because of the complex interfering components and its trace concentration in the matrixes(about ng/g fresh weight).It’s increasingly important for phytohormones to establish purification and detection methods of high selectivity,sensitivity and efficiency,especially for their combination.In this dissertation,the sample pretreatment and quantitative analysis of phytohormones in plant samples have been established based on the combination of molecularly imprinting technology,chromatography and electrochemistry,owing to their respective advantages.Several kinds of phytohormones in Actinidia chinensis and winter flower have been determined by the proposed methods.The contents are as follows:(1)A molecularly imprinted monolith(MIM)was synthesized in a micropipette tip by in situ thermal initiated polymerization using salicylic acid(SA)as template,4-vinyl pyridine as functional monomer,ethylene glycol dimethacrylate as cross-linker,toluene and dodecanol as binary porogen and 2,2’-azobisisobutyronitrile as initiator.The synthesis condition such as the ratio of template molecular,functional-monomer and cross linker was optimized.The micropipette tip could match to a syringe without any other treatmentto perform thepolymer monolith microextraction(PMME).The prepared MIM was characterized by Fourier transform infrared spectrometer(FI-TR),scanning electron microscope(SEM)and thermo gravimetric analysis(TGA).The results confirmed the binary continuous structure of network skeleton with macropore.The extracted SA was determined on a graphene oxide(GO)modified glassy carbon electrode(GCE)by differential pulse voltammetry(DPV),due to the advantages of GO such as nano-scale effect,surface properties,easy handling and strong affinity with biological molecules.The conditions of microextraction andelectroanalysis were optimized,such as type of solvent,sample volume and its flow rate,eluent volume and its flow rate,etc,especially the joint condition between PMME and DPV.The behavior of SA on the GO modified GCE was also investigated,so as the electrochemical analytical conditions,such as the concentration of GO,constitution of buffer solution,the pH,etc.Thus,a new method for the detection of SA in Actinidia chinensis using the MIMC-DPV was established successfully.(2)A conducting molecularly imprinted polymer coating was electrodeposited by cyclic voltammetry(CV)on a stainless steel wire for the selective separation and quantification of cis-Jasmone(CJ)and methyl jasmonate(MeJA)in winter flower,which employed CJ as template molecular,acetic acid thiophene(AAT)as functional monomer,3,4-ethylenedioxythiophene(EDOT)as cross-linker,4-methylbenzene sulfonic acid as supporting electrolyte.Synthesis condition of the conductingmolecularly imprinted coating were optimized,such as the ratio of template and functional monomer,scan rate,scan circles and so on.The coating was characterized by FI-TR,SEM and TGA.The experimental conditions such as salinity,extraction time and temperature,stirring rate were investigated.By coupling with gas chromatography(GC),the CJ and MeJA were quantitatively determined,and the conducting molecularly imprinted polymer coating displayed favorable performance.According to the head-space microextraction,the molecularly imprinted polymer coating was successfully applied for the selective separation and quantitative analysis of CJ and MeJA in buds and petals of winter flower samples. |
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