A Simple Separation Method with a Microfluidic Channel Based on Alternating Current Potential Modulation

A simple separation and detection system based on an electrochemical potential modulated microchannel (EPMM) device was developed for the first time. The application of alternating current (AC) potential to the microfluidic separation channel walls, which were composed of screen printed carbon electrodes, resulted in the oscillation and fluctuation of analytes and in the formation of a perfect flat flow front. These events resulted in an increase in the effective concentration and in the fine separation of samples. The performance of the EPMM device was examined through the analysis of endocrine disruptors (EDs) and heavy metal ions (HMIs) as model compounds. The analytical parameters that affected the separation and detection of EDs and HMIs were studied in terms of AC amplitude, AC frequency, flow rate, buffer concentration, pH, detection potential, and temperature. The separation efficiency was evaluated through measurements of the theoretical plate number (N), the retention time, and the half-peak width. Linear calibration plots for the detection of EDs and HMIs were obtained between 0.15 and 250.0 nM (detection limit 86.4 +/- 2.9 pM) and between 0.01 and 10.0 nM (detection limit 9.5 +/- 0.3 pM), respectively. The new device was successfully demonstrated with authentic and real samples.