PMMA Capillary Electrophoresis Chip Amperometric Detection

Capillary electrophoresis chip (CEC) is composed of capillary and detection. It can obviously improve its portability and maneuverability. Detection by ampere, which is the most commonly employed electrochemical method for conventional capillary electrophoresis chip, has a high sensitivity and efficiency. It is highly regarded by most researchers.It introduces the theory of the ampere detection on capillary electrophoresis chip. It describes capillary electrophoresis chip structure which designed by myself, the choice of materials and fabrication methods used for PMMA as raw material. In order to design a rational electrode structure in microchip, I analyze the amperometric detection theory. Identify the impact of factors signal as follows: the choice of electrode material, electrodes placed between the position, buffer concentration and pH, micro-tube's size and structure. For these factors, I analyze and design the work electrode, reference electrode and the auxiliary electrode materials, the size of these electrodes and the layout of three electrodes in three-electrode system. Choose the appropriate buffer concentration and pH through experiments. Analyze and design the micro-chip channel shape and layout through pipeline right-of-proliferation and fluid mixture of theoretical analysis in order for the optimum pipeline size and structure. Research the PMMA capillary electrophoresis chip process. In the original process, optimize the drilling, pressure electrode, cleansing and the bonding . After deeply study the key technologies -- bonding method, I come to the electrode materials and PMMA bonding the best temperature is 70℃, pressure is 40 MPa, bonding time is 15 minutes and the PMMA the same kind of material the best bonding temperature is 90℃, with no pressure, bonding time is 5 minutes. Using self-made single-channel capillary electrophoresis chip test a borax buffer solution to the seepage --μ_eo is 3.62×10^-3cm²/Vs. According to electroosmotic flow and the value calculated, the sampling time is 27s and the separation time is 122s. Cyclic scan was used to determine the micro-electrode system arginine samples and the detection of potential is -0.6V. These results demonstrate the structure of the chip reasonable and can be used for amperometric detection.