Before electrophoresis, the channels of each glass chip were treated by rinsing with deionized water, 0.1M NaOH, and again with deionized water for 10min each. The reservoirs were cleaned and the reservoir for sample solution was filled with sample solution, while all other reservoirs were filled with running buffer. Each of the corresponding pipette tips on the micro-channel chip was filled with their respective solution. Injection was carried out by applying the desired potential, 1200 V, between the sample reservoir and the grounded detection reservoir for 3 s, while all other reservoirs were allowed to float. Separation was performed by switching the high-voltage contacts and applying the corresponding separation voltages to the running buffer reservoir with the detection reservoir grounded. As soon as the voltage was switched to perform electrophoresis separation, the electrochemical analyzer was actuated to record signals.