毛细管电泳非接触电导检测电极结构的设计

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200 μm，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，三明治式电极结构的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220 V/cm的分离场强下两种无机离子可在40 s内实现完全的分离检测。得到的结果显示三明治式的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。

Abstract

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.

参考文献

[1] MAYRHOFER K, ZEMANN A J, SCHNELL E. Capillary electrophoresis and contactless conductivity detection of Ions in narrow inner diameter capillaries［J］. Anal. Chem. 1999,71:3828-3833.

[2] MIKA J,OPEKAR F, COUFAL P, et al.. A thin-layer contactless conductivity cell for detection in flowing liquids［J］. Analytica Chimica Acta, 2009,650:189-194.

[3] PORMSILA W, STEPHAN KRAHENBUHLC, PETER C. Hauser. Capillary electrophoresis with contactless conductivity detection for uric acid determination in biological fluids［J］. Analytica Chimica Acta, 2009,636:224-228.

[4] HUANG Z Y, JIANG W W, ZHOU X M, et al.. A new method of capacitively coupled contactless conductivity detection based on series resonance［J］. Sensors and Actuators B, 2009,143:224-228.

[5] MARKE TA RYVOLOVA,PREISLER J, FRANTISEK FORET, et al.. Combined Contactless Conductometric, Photometric, and Fluorimetric Single Point Detector for Capillary Separation Methods［J］. Anal. Chem., 2010,82:129-135.

[6] ALVES J G,FRACASSI J A, BLANESA L, et al.. Understanding Capacitively Coupled Contactless Conductivity Detection in Capillary and Microchip Electrophoresis. Part 2. Peak Shape, Stray Capacitance, Noise, and Actual Electronics［J］. Electroanalysis, 2005,17(13):1207-1214.

[7] FRACASSI J A, SILVA D, LAGO D. An oscillometric detector for capillary electrophoresis［J］. Anal. Chem. 1998, 70:4339-4343.

[8] KUBAN P,HAUSER P C. Effects of the cell geometry and operating parameters on the performance of an external contactless conductivity detector for microchip electrophoresis［J］. Lab Chip. 2005,5:407-415.

[9] LICHTENBERG J,ROOIJ N F. E verpoorte. A microchip electrophoresis system with integratedin-plane electrodes for contactless conductivity detection［J］. Electrophoresis. 2002, 23:3769-3780.

[10] 古江春, 王泽毅，洪先龙. 三维寄生电容边界元计算的半解析积分方法［J］.电子学报. 2000，28(5):820-821.

GU J C, WANG Z Y, HONG X L. Semi-analytical Integration Approach in 3-D Parasitic Capacitance Computation with BEM［J］. Actaelectronicasinica, 2000，28(5):820-821.(in chinese)

[11] 侯劲松, 王泽毅, 周春玲. 二维任意形状寄生电阻电容的边界元计算［J］.计算机辅助设计与图形学学报. 1996, 8(3):215-221.

HOU J S, WANG Z Y, ZHOU C L. The calculation of two-dimensional parasitic resistance and capacitance with realistic shapes by using the boundary element method［J］.Chin. j. CAD & CG. 1996, 8(3):215-221.(in chinese)

[12] LIU X W, ZHANG H F, SHAO X H, et al.. Contactless conductivity detector for capillary electrophoresis chip［J］. Nanotechnology and Precision Engineering. 2009,7(2):123-126.

[13] LIU H T, WENG Z Y, XU Y, et al.. Design of contactless conductivity detecting［J］. Opt. Precision Eng., 2009,17(7):1640-1645. (in Chinese)

[14] ZHANG H F, LIU X W, LI H T, et al.. Effect of the detector parameters on the sensitivity of contactless conductivity detector for microchip electrophoresis［J］. ICSC. 2008,355-358.

张海峰, 邵宪辉, 刘晓为, 王蔚. 毛细管电泳非接触电导检测电极结构的设计[J]. 光学精密工程, 2011, 19(5): 1068. ZHANG Hai-feng, SHAO Xian-hui, LIU Xiao-wei, WANG Wei. Design of detection electrode on contactless conductivity detector for capillary electrophoresis[J]. Optics and Precision Engineering, 2011, 19(5): 1068.

毛细管电泳非接触电导检测电极结构的设计

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