Research On The Preparation,Characterization Of Nicotine Molecularly Imprinted Polymer And Application Of Solid-phase Extraction

In this thesis,the research progress of molecular imprinting technique,application of molecularly imprinted polymers and the analytical methods of nicotine were reviewed in detail.Nicotine surface molecularly imprinted polymers(SMIPs)and thermal-sensitive nicotine surface molecularly imprinted polymers(TMIPs)were prepared.The performance of SMIPs used as solid-phase extraction adsorbents was evaluated.Primary studies in the thesis are included as following:1.SMIPs were prepared on the surface of silica nanospheres using nicotine as a template,MAA as a functional monomer and EGDMA as a crosslinker.SMIPs were characterized by FT-IR,TGA,SEM and TEM.The equilibrium adsorptionexperiments were used to evaluate the adsorption ability of SMIPs,the results showed that SMIPs have good specific recognition ability,to ward nicotine.The adsorption capacity of SMIPs was up to 247.0 μmol/g,the imprinting factor was 4.40 when the initial nicotine concentration was 3.5 mmol/L.2.A new method of solid-phase extraction using SMIPs as adsorbents coupled with gas chromatography-mass spectrometry was developed for determination of nicotine in zero-level refill liquids of electronic cigarettes.Satisfactory average recoveries were achieved ranging from 76.17%to 83.85%with relative standard deviations lower than 6.41%under the optimized solid-phase extraction conditions.3.The adsorption performance and selectivity of the SMIPs were evaluated,the results showed that the SMIPs have good adsorption ability for both nicotine and cotinine.Finally,the SMIPs was successfully used as the solid-phase extraction adsorbents to simultaneous extraction and separation of nicotine and cotinine from human hair samples by optimizing the experimental conditions of the washing and elution steps in the extraction process.The results showed that the nicotine recoveries were in the range of 85.10～113.3%,with the relative standard deviations lower than 4.55%.The recoveries of cotinine in the range of 74.21～80.53%,with the relative standard deviations lower than 4.64%.4.The TMIPs was synthesized using nicotine as a template,MAA as a functional monomer,NIPAM as a thermosensitive monomer and EGDMA as a crosslinker.The thermal-sensitive properties of the TMIPs were characterized by dynamic light scattering,the results showed that the LCST of TMIPs was in the range of 30～40 ℃.In addition,the adsorption experiments showed that TMIPs had good adsorption capacity for nicotine and good response to temperature.The adsorption amount of TMIPs decreased significantly from 149.6 μmol/g at 25℃ to 79.44 μmol/g at 65 ℃.