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研制了一种集成于硅基电泳芯片分离沟道末端侧壁的新型四电极电容耦合非接触电导检测器.研究了该电导检测器的等效模型,对等效电路模型中的参数进行了公式推导,并讨论了影响电导检测响应灵敏度的相关因素.采用深刻蚀及离子注入加工技术制得了用于电导检测的立体电极.制作了基于锁相放大原理的信号处理电路,对该电导检测的频率响应及灵敏度进行了测试分析.实验结果表明,当激励信号频率为300 kHz时,该电导检测器具有最佳线性度;不同浓度Na+溶液响应电压差值为5 mV;检测限达到10-8mol/L;且成功实现了Na+和Li+混合无机阳离子的电泳分离在线检测.
A novel four-electrode capacitively coupled non-contact conductivity detector integrated with the electrophoresis chip separation trench sidewall was developed. The equivalent model of the conductivity detector was studied and the parameters in the equivalent circuit model were calculated by the formula And the related factors that affect the sensitivity of the conductance detection were discussed.The deep electrode and ion implantation process were used to fabricate the three-dimensional electrode for conductance detection.The signal processing circuit based on the principle of lock-in amplification was fabricated, the frequency of the conductance detection Response and sensitivity.The experimental results show that the conductivity detector has the best linearity when the excitation signal frequency is 300 kHz.The response voltage difference between different concentrations of Na + solution is 5 mV.The detection limit reaches 10-8 mol / L; and online detection of electrophoretic separation of mixed inorganic cations of Na + and Li + has been successfully achieved.