Integrated Universal Conductivity Detection for Chip Electrophoresis
On-column conductivity detection in chip electrophoresis was achieved by active coupling the high electric field inherent to electro-osmosis with 2 sensing electrodes connected to the main capillary channel through 2 side detection channels forming a double-T. The method was demonstrated by using a glass chip with a separation channel incorporating 2 double-Ts, one of which was used for sample introduction, and the other for detection. Both numerical simulation and experiment results show that the potential difference between the 2 side detection channels is directly related to the conductivity of the solution passing through the channel. A detection limit of 15μM (600 ppb or 900fg) was achieved for K<+> in a 2mM Tris-HCl buffer (pH 8.7) with a linear range of 2 orders of magnitude. The proposed detection method avoids micro- fabrication of sensing electrodes within the separation channel and prevents any direct contact of the electrodes with the solutes passing through the detection cell; meanwhile, conductivity detection and electrophoresis separation are seamlessly integrated in the same separation channel using the same high voltage power as a common activator.
Dc conductivity detection Chip electrophoresis Electric coupling
Zhi-Yong Wu Fang Fang Jacques Josserand Hubert H Girault
Research Center for Analytical Sciences, Northeastern University, Shenyang, China Laboratoire dElectrochimie Physique et Analytique, Ecole Polytechnique Federale de Lausanne, CH-101
国际会议
The First Shenyang International Colloquium on Micrifluidics(首届沈阳国际微流控学术论坛)
沈阳
英文
159-162
2007-10-21（万方平台首次上网日期，不代表论文的发表时间）