【作者】 李晓慧；

【导师】 唐婷范；

【作者基本信息】 广西科技大学 ， 化学工程与技术， 2020， 硕士

【摘要】 多酚类物质是普遍存在于植物界,具有抗氧化能力、抗炎、抗过敏、抗菌、保护心脏等药理作用的一类物质,由于其利用价值较高,且在自然界分布较广,吸引了越来越多研究者的关注。甘蔗的蔗叶、蔗梢、蔗茎中均含有多酚类物质,其在甘蔗内少数以游离态形式存在,多数与纤维素、蛋白质、木质素、类黄酮、糖基、有机酸以结合的形式存在于植物组织的初生壁和次生壁中,这增大了多酚类物质提取和分离的难度。固相萃取技术（SPE）作为目前常用的样品预处理技术,常与色谱分析结合,用于复杂体系中待测物质的分离分析,简化了样品预处理过程并提高了检测灵敏度。而整体柱作为近年来新兴的一门技术,因其具有制备简单、稳定性好、疏松多孔、成本较低等优点,在用作样品前处理的固相萃取柱方面也具有广阔的应用前景。本文使用不同聚合物单体,采用原位聚合的方法制备得到多种整体柱,并将其作为SPE柱,用于甘蔗中多酚类物质的样品预处理,并与加压毛细管电色谱（p CEC）联用对样品进行了分离测定,考察了采用不同单体得到的SPE整体柱对甘蔗中多酚类物质萃取过程的影响及一般规律。在此基础上,以甲基丙烯酸丁酯（BMA）为单体,掺杂金属有机骨架材料（MOFs）,制备了MIL-53（Al）-polymer整体柱,增大了整体柱的比表面积,进一步增加了甘蔗中多酚类物质的富集倍数,提高了检测灵敏度,简化了样品预处理过程。主要研究内容与结果如下:1.建立了甘蔗中三种多酚类物质:绿原酸、阿魏酸、表儿茶素分离测定的p CEC法。实验对流动相比例、缓冲盐p H、缓冲盐浓度、分离电压、流速等色谱条件进行了考察。在最优的色谱条件下[流动相:15.0 mmol/L Na H₂PO₄+12.5 mmol/L庚烷磺酸钠（p H 5.0）/甲醇（50:50,V/V）;流动相总流速:0.06 m L/min;分离电压:1 k V;检测波长220 nm],绿原酸、阿魏酸、表儿茶素三种多酚类物质线性关系良好,相关系数（r）分别为0.9978、0.9922、0.9971,平均回收率分别为96.79%、100.71%、99.01%,成功对甘蔗中三种多酚类物质进行了分离检测。2.以丙烯酰胺（AM）为单体,通过原位聚合法在聚丙烯材料注射器内合成了聚丙烯酰胺-乙二醇二甲基丙烯酸酯（poly（AM-co-EDMA））固相萃取整体柱。通过红外光谱仪（FT-IR）、扫描电子显微镜（SEM）对其进行表征,表明poly（AM-co-EDMA）整体柱聚合效果良好,内部结构稳定。同时,对影响该整体柱性能的因素进行了研究,并优化了该SPE整体柱对甘蔗中的多酚类物质进行SPE时的各个条件,建立了poly（AM-co-EDMA）-p CEC联用分离测定甘蔗中多酚类物质的方法。结果表明使用该方法进行样品预处理操作简单、灵敏度高,绿原酸和阿魏酸的平均回收率分别为99.43%、98.51%,结果满意。3.分别以乙烯基吡咯烷酮（NVP）、苯乙烯（ST）、对乙烯基苯硼酸（VPBA）、甲基丙烯酸丁酯（BMA）为单体,原位合成了一系列不同极性的整体柱,并分别以各整体柱作为SPE柱,探索不同极性SPE整体柱萃取甘蔗中多酚类物质的一般规律。通过红外光谱仪（FT-IR）、扫描电子显微镜（SEM）、微孔物理化学吸附仪（BET）对各整体柱进行表征,同时,对影响整体柱性能的因素进行了研究。选择聚对乙烯基苯硼酸-乙二醇二甲基丙烯酸酯（poly（VPBA-co-EDMA））整体柱作为最优整体柱。实验优化了使用该SPE整体柱进行SPE时的各个影响因素,建立了poly（VPBA-co-EDMA）-p CEC联用分离测定甘蔗中多酚类物质的方法。该方法样品预处理简单,绿原酸和阿魏酸的平均回收率分别为99.87%、100.71%。4.以甲基丙烯酸丁酯（BMA）为单体,在整体柱预聚液中加入MIL-53（Al）MOFs材料,通过原位聚合法合成了掺杂MIL-53（Al）MOFs材料的MIL-53（Al）-polymer整体柱。通过红外光谱仪（FT-IR）、扫描电子显微镜（SEM）、微孔物理化学吸附仪（BET）、X射线衍射仪（XRD）对其进行表征。同时,考察了掺杂MIL-53（Al）材料的量对该整体柱萃取性能的影响,并优化了该整体柱对甘蔗中多酚类物质进行SPE时的条件,建立了MIL-53（Al）-polymer-p CEC联用分离测定甘蔗中多酚类物质的方法,结果满意。更多还原

【Abstract】 Polyphenols are ubiquitous in the plant kingdom,with antioxidant,anti-inflammatory,anti-allergic,antibacterial,heart protection and other physiological functions.Because of their high utilization value and wide distribution in nature,they have attracted More and more researchers are paying attention.Sugarcane leaves,cane tips,and cane stems all contain polyphenols.A few of them are in free form in sugarcane,and most are combined with cellulose,protein,lignin,flavonoids,sugar groups,and organic acids.It exists in the primary and secondary walls of plant tissues,which increases the difficulty of extraction and separation of polyphenols.Solid-phase extraction technology（SPE）,as a commonly used sample pretreatment technology,is often combined with chromatographic analysis for the separation and analysis of substances to be tested in complex systems,which simplifies the sample pretreatment process and improves the detection sensitivity.As a new technology emerging in recent years,the monolithic column has broad application prospects as a solid phase extraction column for sample preparation because of its advantages of simple preparation,good stability,loose porosity,and low cost.In this paper,different monomers are used to prepare a variety of monolithic columns by in-situ polymerization,and they are used as SPE columns for sample pretreatment of polyphenols in sugarcane,and are combined with pressurized capillary electrochromatography（p CEC）to separate and measure the sample,the effect and general rule of SPE monolithic columns obtained with different monomers on the extraction process of polyphenols in sugarcane were investigated.On this basis,using butyl methacrylate（BMA）as the monomer and doping metal-organic framework materials（MOFs）,a MIL-53（Al）-polymer monolithic column was prepared,which increased the specific surface area of the monolithic column,increase the enrichment factor of polyphenols in sugarcane,improve the detection sensitivity,and simplify the sample pretreatment process.The main research contents and results are as follows:1.Established the p CEC method for the separation and determination of three polyphenols in sugarcane:chlorogenic acid,ferulic acid,and epicatechin.The experiment investigated the chromatographic conditions such as mobile phase ratio,buffer salt p H,buffer salt concentration,separation voltage and flow rate.Under optimal chromatographic conditions[mobile phase:15.0 mmol/L Na H₂PO₄+12.5 mmol/L sodium heptane sulfonate（p H 5.0）/methanol（50:50,V/V）;total flow rate of mobile phase:0.06 m L/ min;separation voltage: 1 k V;detection wavelength 220 nm],chlorogenic acid,ferulic acid,and epicatechin have a good linear relationship,with correlation coefficients（r）of 0.9978,0.9922,and 0.9971,and average recovery rates of 96.79%,100.71%,and 99.01%,respectively.Three polyphenols in sugarcane were separated and tested.2.Using acrylamide（AM）as the monomer,polyacrylamide-ethylene glycol dimethacrylate（poly（AM-co-EDMA））monolithic column was synthesized in a polypropylene material syringe by in-situ polymerization.It was characterized by infrared spectrometer（FT-IR）and scanning electron microscope（SEM）,which showed that poly（AM-co-EDMA）monolithic column had good polymerization effect and stable internal structure.At the same time,the factors affecting the performance of the monolithic column were studied,and the various conditions when the SPE monolithic column was used for the SPE of polyphenols in sugarcane were optimized,and the poly（AM-co-EDMA）-p CEC combination method was established for separating and measuring polyphenols in sugarcane.The results show that the method is simple and has high sensitivity for sample pretreatment.The average recoveries of chlorogenic acid and ferulic acid are 99.43%and 98.51%,respectively,and the results are satisfactory.3.Using vinylpyrrolidone（NVP）,styrene（ST）,p-vinylphenylboronic acid（VPBA）and butyl methacrylate（BMA）as monomers,a series of monolithic columns with different polarities were synthesized in situ,each monolithic column was used as an SPE column to explore the general rule of extracting polyphenols from sugarcane with monolithic SPE monolithic columns of different polarities.Each monolithic column was characterized by infrared spectrometer（FT-IR）,scanning electron microscope（SEM）,micropore physical chemical adsorption（BET）,and at the same time,the factors affecting the overall column performance were studied.The poly（VPBA-co-EDMA）monolithic column was chosen as the optimal monolithic column.The experiment optimized the various influencing factors when using the SPE monolithic column for SPE,and established a poly（VPBA-co-EDMA）-p CEC combined separation and determination method for polyphenols in sugarcane.Sample preparation in this method is simple,and the average recovery rates of chlorogenic acid and ferulic acid are 99.87%and 100.71%,respectively.4.Using butyl methacrylate（BMA）as the monomer,add MIL-53（Al）MOFs material to the overall column prepolymerization solution,MIL-53（Al）-polymer monolithic columns doped with MIL-53（Al）MOFs were synthesized by in-situ polymerization.It was characterized by infrared spectroscopy（FT-IR）,scanning electron microscope（SEM）,microporous physical chemical adsorption（BET）,and X-ray diffractometer（XRD）.At the same time,the effect of the amount of doped MIL-53（Al） material on the extraction performance of the overall column was investigated,and optimize the conditions of this monolithic column for SPE of polyphenols in sugarcane,A method for separation and determination of polyphenols in sugarcane by MIL-53（Al）-polymer-p CEC was established with satisfactory results.更多还原