【作者】 李雷光；

【导师】 陈昌国；

【作者基本信息】 重庆大学 ， 物理化学， 2009， 硕士

【摘要】 高效毛细管电泳色谱(HPCE)是近二十年来发展最快的分析测试方法之一,它具有分离效果好、灵敏度高、测量时间快、消耗低等特点。而电容耦合非接触电导检测(C4D)则是HPCE的一种新型电导检测技术,是近年来的研究热点。本文结合自行研制的非接触电导检测器和毛细管电泳仪组装了毛细管电泳离子色谱仪,并对其有关内容进行了系统的研究。首先采用VB6.0语言开发了色谱工作站。提出了基于VB的数据处理自动识别色谱峰的新算法,通过分析谱峰信号的斜率变化来确定峰曲线的起点、顶点和终点,进而计算峰面积和样品浓度。方法快速、准确,对特殊峰和微小峰的处理非常有效。仿真实验表明:在较大噪音时也可以得到满意的效果,可以应用于毛细管电泳离子色谱数据处理。在毛细管电泳离子色谱法的研究中,通过优化实验条件来改善峰型以达到电泳分离检测的总体效果。采用2-N-吗啡啉乙磺酸(MES)-L-组氨酸(L-His)为缓冲体系,对K+、Ba2+、Ca2+、Na+、Mg2+、Li+几种常见碱金属和碱土金属离子在3.5min内实现了分离检测,同时考察了缓冲液的种类、浓度、添加剂、pH值、激发电压、激发频率对分离的影响。当用pH=6.05缓冲液:25 mmol/L MES/His+20μmol/L CTAB(十六烷基三甲基溴化铵),在10kV分离电压、120kHz激发频率、60Vp-p激发电压时,体系有最佳的分离效果。六种离子的检测限依次为:0.1、1.0、1.0、1.0、1.0和2.0μmol/ L,响应线性范围为10-6～10-3mol/ L,相关系数R>0.985。在电渗流峰的变化规律系统研究中,采用了毛细管电泳-非接触电导检测法,并以10 mmol/L MES/L-His为缓冲溶液。结果表明:随着KCl溶液浓度的减小,电渗流峰出现由正峰逐渐变为负峰的现象,并结合非接触电导检测原理、组氨酸的特性和质子平衡方程进行了详细的解释,对电渗流的研究具有参考价值。用交流阻抗法研究了电容耦合非接触电导检测池的阻抗特性,考察了不同电间距、电极长度、毛细管内径和电极材料对检测池阻抗的影响。结果表明:检测池的阻抗随着电间距和电极长度的增大而增加,同时电极与毛细管壁之间的空隙也会影响阻抗的大小。高频时,除去毛细管外层保护层会使检测池的阻抗减小,从而提高检测器的灵敏度。采用铜箔作电极,有效地消除了电极与毛细管壁之间的空隙,使得检测池阻抗在低频时减小。通过Zview软件拟合,提出了简单的拟合等效电路。更多还原

【Abstract】 High Performance Capillary Electrophoresis (HPCE) was one of the most rapid developing method in recent twenty years. It has the characteristics of high performance, short measurement time, low consumption, high sensitivity, and so on. And capacitively coupled contactless conductivity detection(C4D) is a new conductivity detection method in HPCE, which is the researching hot-point in recent years. In this dissertation, the capillary electrophoresis ion chromatography apparatus is built by conbining the C4D and capillary electrophoresis instrument. The correlation content of capillary electrophoresis ion chromatography is studied systematically.Chromatography work station was developed by Visual Basic 6.0. A new algorithm of chromatographic peak identification based on VB is proposed. Based on the change of the chromatogram signal’s slope among positive, zero and negative. The algorithm can fix the position and types of each feature point of the signal curve, then to calculate their areas and related concentrations. Some small and abnormity kinds of chromatographic peaks can be reliably detected and distinguished. The simulation experiment shows that this work station can get the satisfied results. It can applied to data process of capillary electrophoresis ion chromatography.The purpose of separation was achieved by optimizing condition in the capillary electrophoresis ion chromatography detection system. Separation of six alkali and alkaline earth metal ions (Li +, Na+, K+ , Mg2 +, Ca2 + and Ba2 + ) can be done within 3.5 min with electrolytes consisting of 2-(N-morpholino) ethanesulfonic acid (MES) and L-histidine (L-His). The effects of separation parameter, such as type and concentration of buffer solution, pH, additives, separation voltage, excition frequency, excition voltage(Vp-p), on the separation were studied. A good resolution was achieved using 25 mmol/L MES/His+20μmol/L CTAB buffer solution at pH=6.05, 10kV separation voltage, 60Vp-p and 120kHz excition frequency. Under the optimal condition, the detection limits for the six cation were 0.1,1.0,1.0, 1.0, 1.0 and 4.0μmol/L, respectively, with linear ranges from 10-6 to 10-3 mol/L (corretion coefficient R > 0.985) .The change rule of electroosmotic flow (EOF) peak was studied by capilly electrophoresis with C4D and MES/L-His was used as the separation electrolyte . As a result, the change of the EOF peak is from positive peak to negative peak with the decrease of the concentration of KCl solution. The phenomenon was rationally explained through the principle of C4D, the property and proton ionization equilibria of L-His. Therefore it was valued for the research of EOF.The impedance characteristics of C4D cell was experimently examined for different cell parameters by Alternative Current Impedance (ACImp) technique. The effect of the gap between the electrodes, electrodes material, the radius of the capillary and the length of the electrodes on the impedance behavior of C4D cell has been studied. As a result, the impedance increased with increasing gap between the electrodes and the length of the electrodes. The impedance also increased with increasing the gap between the capillary wall and electrode. The cell impedance decreased without the Polyimide- coated in the high frequency region. The impedance decreased with electrodes made by copper foil. Because it can eliminate the gap between the capillary wall and electrode. The axial contactless conductometric detector can effectively be described by the simplest possible equivalent circuitry consisting of a capacitor, resistor, a second resister and a Warburg impedance .更多还原