This paper presents a new structure of MCE chip on PMMA substrate prepared to improve the original chip structure
with UV absorbance detection mode. The chip microchannels are fabricated by CNC milling and packaged with hot
embossing process at the processing condition of 80°C, 5min, 0MPa with a manual powder pressing machine. All the
micro-channels is 150&mgr;m * 150&mgr;m. Mobility &mgr;eo of PMMA MCE chip is 2 9.15e-004cm Vs in the solution of
10mmol/L Na2CrO4 and 0.5mmol/L CTAB. Adopting indirect UV photometric detection mode, the inorganic anion Cl-
capillary electrophoresis is carried out with an in-house UV detection system. The BGE buffer is 10 mmol/L Na2CrO4
and 0.5mmol/L CTAB, and the electrophoresis voltage is 616V. Test widow is 0.3*2 mm2. Test results indicate that both
in-house UV detection system and MCE chip of PMMA substrate have the basic function and could be applied in the
chemical analysis field.
Microfluidic components are basic tools in microanalysis systems. A simple structure PDMS micro valve is described. Driven by the PZT piezoelectric actuator, this microvalve could realize to control the liquid flow rate in the microliter or submilliliter scale. The fabrication method about the PZT piezoelectric thick film with the screening printing technique and the Polydimethylsiloxane (PDMS) valve body with the soft lithography technique are presented. The optimal PZT film processing annealing temperature parameter at 800°C in 60 min could be observed, the PZT grain size is about 1μm or more. Then the silicone substrate and the drilled PDMS top substrate are bonded together with the oxygen plasm to form the chamber. The overall dimensions of the valve are 10mm x 10mm x 2mm. While the dead volume is 0.1 ml, and the inner diameter of the valve seat is 6 mm. Finally, the performance of the PDMS valve is tested.
Microchip electrophoresis technique have been developed fully these years, especially the detection methods have been the research focuses. With the help of MEMS technique, the system integrating function are more and more. This paper presented a novel design and fabrication method about this electrophoresis chip with the detection electrodes. The two-layer structure, one is PDMS
substrate to fabricate the electrophoresis microchannel, the other is the glass substrate with the Pt electrodes, are bonded together. The soft lithography with the two molds is developed to accommodate
the PDMS curing and peeling off. Then the inorganic cation Cu2+ is introduced and tested the project feasibility. All these works are laid a stable foundation for the chip appliance.
The miniaturized system is fabricated on the PMMA substrate including the CE separation chip and the PZT micropump chip. Adopted the PZT materials deformation as actuation force, the micropump is of the bi-direction flow capability to finish the self-rinsing process. The dimension of this micropump is 14×14×3 mm3. The volume of the pump chamber is about 20mm3. The pump can produce a maximum back pressure of 2m H2O and a maximum flow rate of 13 mL/min under 145 V, 100Hz squired wave power supply. The optimized capillary channel structure is chosen by the width of 50 μm, the depth is 20μm and the effective separating length is 50mm with round corner sinuous channel. The whole chip area is 55×20mm2.