Study On Integration System Of Low-voltage Capillary Electrophoresis Chip

Capillary electrophoresis microchip is a microdosage separate and analysis instrument, which has many advantages of high-efficiency, high-speed, high-throughput, low-consumption, etc. It has become one important means for proteomics, clinical medicine, drug screening and others. However, the injection and separation processes of capillary electrophoresis microchip often require high voltage to drive, and the detector volume of capillary electrophoresis micochip is often much larger than the size of microchip itself, so that, the miniaturization of entire analysis system is facing many difficulties. In this dissertation, the integration system of capillary electrophoresis microchip has been studied, and aiming to the integration system characteristic which include the low-voltage, miniaturization and integration.The VHDL-AMS model of in-plane four-electrode contactless conductivity detector of electrophoresis microchip is built using VHDL-AMS language, and the effect parameters of output frequency response for contactless conductivity detector is investigated, such as the dielectric constant of electrolyte solution, insulation materials, the thickness of insulation materials, the distance of any two adjacent electrodes, the width of detection electrode and so on. On this basis, the detection methods suitable for chip electrophoresis are discussed. Especially, the orthogonal vector lock-in amplifier and cross-correlation-chaos detection methods are studied. According to the detection characteristics of contactless conductivity detector, the wavelet de-noising method is selected to reduce noise. And the extraction of electrophoresis chromatography of microchip based on short-time energy difference function is studied.The preparation technologies of ITO array-electrode, micro-channel mold and PDMS micro-channel are studied. Simultaneously, the experimental low-voltage capillary electrophoresis separation chips with ITO array-electrode is developed and fabricated based on ITO glass substrate.For satisfying the research of low-voltage capillary electrophoresis separation chip integrated system, a detection and control system based on SOPC embedded technology is present. According to the micro-array electrode distribution features and the circuit structure, a moving control algorithm suitable for low-voltage control strategy is proposed. The moving control IP core for micro-array-electrode of low-voltage capillary electrophoresis chip is developed using VHDL language. By eight chips multiplexers, MAX306, ordered arrangement, the directional moving electric field, which can drive the components to be determined directional migration, can be formed. At the same time, for satisfying the requirements of driving micro-array-electrode of low-voltage capillary electrophoresis microchip and excitating the contactless conductivity detector, two kinds of four-phase signal sources are designed. One is based on MAX038 function generator, another is based on DDS technology. According to the features of contactless conductivity detector, the corresponding dual differential impedance to voltage converter circuits are designed for impedance to voltage conversion and signal amplification, and the detection circuits based on analog lock-in amplifier are designed to realize detector output's AC signal to DC signal conversion. The SOPC system with NIOSâ…¡soft-core processor, which is customized using SOPC Builder, is used to control coordinated functional modules. The PC detection program based on C++Builder is designed for low-voltage electrophoresis separation chip conductivity weak signal detection demand. On this basis, the preliminary experiments of low-voltage electrophoresis separation chip integration system were tested, and the related issues of future work are proposed.