毛细管电泳非接触电导检测电极结构的设计  

Design of detection electrode on contactless conductivity detector for capillary electrophoresis

作　　者：张海峰[1] 邵宪辉[1] 刘晓为[1,2] 王蔚[1] 

机构地区：[1]哈尔滨工业大学MEMS中心,黑龙江哈尔滨150001 [2]微系统与微结构制造教育部重点实验室,黑龙江哈尔滨150001

出　　处：《光学精密工程》2011年第5期1068-1074,共7页Optics and Precision Engineering

基　　金：黑龙江省自然科学基金资助项目(No.E200917)

摘　　要：针对毛细管电泳非接触电导检测电极间的寄生电容对检测信号的影响,研究了非接触电导检测器检测电极的结构。采用边界元素法研究了毛细管电泳非接触检测电极间的寄生电容,通过静电场软件仿真了两电极之间的电场分布,优化了非接触电导检测的电极结构。根据仿真结果提出了一种三明治式电极结构,其有效电极长度为200μm,解决了传统电极结构寄生电容较大的问题,也克服了传统三电极结构检测电极易于折断的缺点。实验和仿真结果表明,相对于传统的电极结构,三明治式电极结构检测器的寄生电容为10-15 F,减小了一个数量级。另外,该检测器在220V/cm的分离场强下两种无机离子可在40s内实现完全的分离检测。得到的结果显示三明治式电极结构适合于毛细管电泳非接触电导检测,可以提高非接触电导检测法的灵敏度。The structure of detecting electrodes in a conductivity detector was studied to decrease the effect of the stray capacitance between the two electrodes on the detecting signal in capillary electrophoresis.The boundary element method was used to study the stray capacitance of two electrodes in contactless conductivity detection.Then,an electric field software was taken to simulate the electric field distribution of electrodes and to optimize the electrode structure with contactless conductivity.On the basis of simulated results,a novel sandwich electrode structure was proposed to decrease the direct capacitive coupling between the two electrodes.The effective length of the electrode is 200 μm,which decreases the stray capacitance between the two electrodes and overcomes its defect to be easy to breakdown.The experimental and simulation results indicate that the stray capacitance of proposed electrode structure is obout 10-5 F,which has been decreased about one order of magnitude as compared with those of conventional electrode structures.Moreover,two inorganic cations can be separated in 40 s at 220 V/cm separation voltage.In conclusion,the sandwich electrode structure is suitable for the contactless conductivity detection and improves detection sensitivity.

关 键 词：毛细管电泳 非接触电导检测 边界元素法 电极结构 仿真 

分 类 号：O657.8[理学—分析化学]