Investigation of an Ion Migration Channel with Ion Preconcentration and Separation Based on Capillary Electrophoresis

It is challenging to increase the sensitivity and selectivity of the electrochemical sensor to detect harmful metal ions due to tiny mass of metal ions pollution and complex marine. In this work, an ion migration channel is presented for preconcentration and separation of harmful metal ions (Hg2+, Pb2+, Cu2+ and Cr3+) based on capillary electrophoresis (CE), which is composed of polydimethylsiloxane (PDMS) with a length of 1.22 m and inner diameter of 0.30 mm. The optimal detection time of Hg2+, Pb2+, Cu2+, and Cr3+ can be deduced at 13th s, 23rd s, 34th s, and 39th s with the optimal operating voltage of 15 kV by simulating migration of the metal ions. The simulated results show that concentrations of metal ions including Hg2+, Pb2+, Cu2+, and Cr3+ (original concentration of 1 mM) are increased by 278.56 times, 140.76 times, 323.03 times, 795.14 times at the optimal detection time. The experimental results show that concentrations of Hg2+, Pb2+, Cu2+, and Cr3+ ions are increased to 2.76 times, 1.50 times, 1.57 times, and 1.89 times with the same parameters of the simulation. By establishing the ion migration channel before the electrochemical sensor, we realize the ion preconcentration and separation, which is available for detecting the metal ions with an extremely low concentration.