微毛细管电泳芯片安培检测器的研制

【作者】 张欣；

【导师】 张玉林；

【作者基本信息】 山东大学 ， 控制理论与控制工程， 2006， 硕士

【摘要】 发展高效、快速、集成化的生物样品分析方法是当前分析技术(包括生物和化学分析)的研究热点。毛细管电泳芯片因为具有易于实现微型化的特点而发展十分迅速，它是在基于常规毛细管电泳的基本原理和技术基础上，微型化后可一次完成样品的进样、反应、分离和检测等一系列任务的一种多功能、快速、高效和低耗的微型分析仪器。目前它已被成功地应用到药物分析、临床诊断、环境检测等领域中。 毛细管电泳芯片的样品体积很小，因此采用高灵敏度的检测方法是十分必要的。微毛细管电泳芯片检测器的作用是测定被分析样品经系统分离处理后有关组分的组成及其含量，检测器的总体性能将影响整个分析系统的检出限、检测速度、适用范围、体积等指标，是毛细管电泳芯片分析系统的一个关键部分。安培检测法是用于毛细管电泳芯片分离末端的一种检测方法，它灵敏度高、易于微型化，是当前应用在毛细管电泳芯片中最为广泛的电化学检测方法。本论文就是基于这一背景，研制了一种新型的微毛细管电泳芯片安培检测器。 在微毛细管电泳芯片安培检测器的设计中，电化学池通电后产生的微电流信号极其微弱(一般在nA级甚至更小)，往往淹没在噪声中很难采集识别。国内外现有的研究大都采用微电流放大器测定流过电化学池的电流，而微电流放大器反馈电阻的增大会减弱运放的稳定性，增加电路的时间常数，影响整个电路的精度和灵敏度。因此，信号采集放大电路部分的设计就成为微安培检测器设计的重点和难点，也是微安培检测系统设计的核心问题。本设计在恒电位仪反馈回路中串一电阻器采集电流信号，并用数据放大器差动测量电阻两端的电压，该电路能较好的满足微弱电流信号的检测要求，克服了现有一些仪器灵敏度越高稳定性越差的弊端。 微毛细管电泳芯片安培检测系统的自动控制部分是基于32位ARM微控制器LPC2104为核心的控制结构，通过设计相应外围接口电路，实现了程控电压源的控制、自动增益电路的控制、A／D转换结果的读取和处理、按键与报警电路及与上位机的通讯等功能。软件采更多还原

【Abstract】 The hotspot of analytical technology (including biology and chemical analysis) is to develop the high —efficiency, rapid, integrated analytical method of biological samples. Because of easily being miniaturized, the capillary electrophoresis chip developes very rapidly. Based on the basic principles and technology of conventional capillary electrophoresis, it is miniaturized and can complete a series of duties, such as sampling, reacting, separating, detecting, and so on. So the capillary electrophoresis chip is a multi-purpose, fast, efficient and low-consumptive micro-analytical instrument. It has been successfully applied to drug analysis, clinical diagnosis, environmental monitoring, and other fields at present.Because the sample vessel of the capillary electrophoresis chip is small, using high-sensitivity detector is extremely necessary. The function of micro capillary electrophoresis chip detector is to determine the composition and content of samples after the system separation processing. The overall performance of detector will affect the indexes of entire microfluidic chip system, including detection limits, testing speed, the scope and cubage of being used, and so on. The decector is a key part of the analysis system. Amperometric detection is used for the separation terminal of capillary electrophoresis. The application of this detection is the most widespread in the domain of electrochemistry detection because of its high sensitivity and miniaturization. This paper is just based on this background to develop a new micro-amperometric detector.The micro-current signal in the electrochemical cell is extremely weak after electrifying in this design. So it is difficult to be distinguished from the noise. Most of the domestic and foreign existing research use micro-current amplifier measuring the current, but the higher the feedback resistance is, the worse the stability is, which increases time更多还原