Abstract: A glass capillary electrophoresis microchip with integrated amperometric detection cell equipped by replaceable micro-disk working electrode is described. The detection cell was fabricated as a buffer reservoir on the microchip. A micro-electrode-guiding hole, which was in alignment with the exit of the separation channel, was drilled into the bottom edge of the chip. When a micro-disk copper working electrode, the outside diameter of which being matched with the inside diameter of the guiding hole, was inserted into the hole, passed through detection cell and finally got access to the exit of the separation channel, the electrode could be quasi-self-aligned to the channel exit and fixed inside the guiding hole without the help of a micro-positioner. Thus an integrated end-column amperometric detection system with replaceable disk working electrode was established on the microchip. Good reproducibility of the electrode alignment was demonstrated by a 4 1% RSD in the detection of sucrose after repeated(n=9) alignment of a micro-copper disk electrode. The developed michrochip was used for separation and detection of oligosaccharides.

Key words: Microfluidic chip, Capillary electrophoresis, Amperometric detection