【作者】 聂琳；

【导师】 陈波；

【作者基本信息】 湖南师范大学 ， 分析化学， 2016， 硕士

【摘要】 整体材料作为新型色谱材料的重要组成部分,已经广泛应用于微柱液相色谱、毛细管电色谱、制备液相色谱等多个研究领域。相对于传统色谱材料,整体材料不仅具有独特的双孔结构,还具有易于修饰、分离性能好、制备工艺相对简单、化学性质稳定、功能多样、通透性较好等优点。无机整体材料(硅胶整体材料)、有机整体材料、有机-无机杂化整体材料是整体材料的三大类型。每种类型的整体材料都有其比较成熟的制备方法。其中无机整体材料,即硅胶整体材料最常采用的制备方法是溶胶-凝胶法(sol-gel)和干凝胶法。相对来说,溶胶-凝胶法(sol-g el)的反应条件不易控制,得到的整体材料往往出现柱床断裂、脱壁、坍塌等结构缺陷。而干凝胶法的操作过程相对简单,反应条件易于控制,且柱床收缩为壁向,贴壁效果相对较好。本论文主要以硅酸钾(K2O·n SiO2)为硅源,甲酰胺为催化剂(ω=1 0%),采用干凝胶法,在三种不同材质的管柱内原位聚合制备硅胶整体材料。各部分实验中考察了不同的反应条件对硅胶整体材料制备的影响。工作主要包括以下三个方面:1.以硅酸钾(K2O·n SiO2)为硅源,甲酰胺为催化剂(ω=10%),采用干凝胶法,在聚丙烯(PP)离心管(i.d.=2.8 cm)中制备硅胶整体材料。实验过程中重点考察了硅酸钾的来源、反应温度、加热方式、硅酸钾模数n对硅胶整体材料的影响。观察整体材料是否出现明显的收缩、断裂现象,对成型较好的整体材料,通过氮吸附法得到其BET比表面积及等温吸附曲线,材料的微观结构通过扫描电镜进行观察。2.采用干凝胶法,以硅酸钾(K2O·n SiO2)为硅源,甲酰胺为催化剂(ω=10%),在石英毛细管中制备毛细管硅胶整体柱。实验过程中主要考察了毛细管内壁的预处理方法、反应温度、内径大小、硅酸钾模数n对硅胶整体柱的影响,并通过光学显微镜观察毛细管硅胶整体柱是否出现脱壁、柱床坍塌等结构缺陷。3.在玻璃管(i.d.=1.0 cm)中,以硅酸钾(K2O·n SiO2)为硅源,甲酰胺为催化剂(ω=10%),采用干凝胶法制备硅胶整体柱。该部分实验考察了玻璃表面处理方法、反应温度、加热方式、硅酸钾模数n对硅胶整体柱的影响。主要通过观察法和色素层析法对硅胶整体柱的结构性能进行表征。更多还原

【Abstract】 As a novel chromatographic material, monolithic material has been widely applied in μ-HPLC、capillary electrochromatography、preparative HPLC etc. Because of its unique double holes structure, monoliths have good separation performance and can be modified easily. In addition, the advantages of stable chemical properties, function diversity, good permeability as well as easy preparation make monolithic material attract increasing interest.In general, monolithic material can be classified into three categories: organic polymer-based monolith, inorganic monolith (silica-based monolith) and organic-inorganic hybrid monolith. Different types of monolith has different preparation methods. Sol-gel and xerogel are the main preparation methods of silica-based monolith. Because of its unmanageable reaction condition, the silica-based monolith using sol-gel is easy to fall off from tube wall and it often suffers from rupturing, collapsing etc. In comparison, xerogel monolith is easier to prepare, and those structure defects mentioned above do not appear.In the process of xerogel method, potassium silicate was utilized as silicon source, formamide was utilized as catalyst. We have prepared the silica monolithic materials in polypropylene centrifugal tube, quartz capillary and glass tube. The different preparation condition have been investigated. The main work includes the following three aspects:1. Silica monolithic material was fabricated in polypropylene centrifugal tube (i.d.=2.8 cm) by xerogel method. The sources of potassium silicate, the reaction temperature, the heating mode and the modulus of potassium silicate were investigated in our experiment. The structure of silica monolithic material was characterized by SEM, and the BET surface area was determined by nitrogen adsorption method.2. Silica monolithic material was fabricated in quartz capillary by xerogel method. The capillary pretreatment method, the reaction temperature, the capillary inner diameter and the modulus of potassium silicate were investigated in this part. The structure of the different monolith was observed by microscope.3. Silica monolithic material was fabricated in glass tube (i.d.=1.0 cm) by xerogel method. The glass surface treatment method, the reaction temperature, the heating mode and the modulus of potassium silicate were investigated in this experiment. The properties of silica monolithic material were characterized by pigment chromatography mainly.更多还原