Abstract: A novel and facile method for the fabrication of monolithic microfluidic chips in poly dimethylsiloxane)(PDMS) has been presented. The fabrication consists of two steps including channels definition and replica molding. Two micrometeric metal wires, previously welded in the cross section on a co-plane, were spanned over a templet to define microscopic channels. PDMS is then cast against the templet. After the metal wires removed and the templet peeled away, a monolithic replica with enclosed networks of channels is obtained. Scanning electron microscopy and CCD imaging demonstrated that the cross-section of two channels was complete contact and channel inner well is smooth. A microchip capillary electrophoresis system was constructed by integrating the monolithic microchip with a chemiluminescence detection, and its performances was demonstrated by the separation and the detection of two amino acids such as arginine and aspartic acid without derivatization procedures. Excellent separation with the resolution of 2.45 within 80 s was achieved with the concentration detection limit(S/N=3) of 3.50 μmol/L for arginine.

Key words: Monolithic chip, Poly(dimethylsiloxane), Chemiluminescence detection, Microchip capillary electrophoresis, Amino acids