A new designed cell for luminol based electrochemiluminescence by bi-potentiostatic excitation for flow-injection analysis

•A new luminol-based ECL cell was designed by bi-potentiostatic excitation.•Four electrodes were artfully fixed in a home-made flow ECL cell.•Continuous and constant ECL signal could be obtained on this ECL cell.•The cell provides higher sensitivity than pulsed mode and successfully employed to determine the activity of antioxidants.

A new designed luminol-based electrochemiluminescent (ECL) cell by bi-potentiostatic excitation was developed for the utilization as a coupled-detector of a flow injection analysis system (Bi-ECL–FIA). In this flow cell, four electrodes were fixed in, here a piece of indium tin oxide coated glass was applied as one of the working electrodes while another Pt net served as second one. Two electrolysis voltages from a dual-potentiostat powered two working electrodes. Thus, continuous and constant ECL signal could be obtained. After optimizing the experimental conditions, it was showed that the Bi-ECL–FIA system provided higher sensitivity than conventional pulsed mode. The response of hydrogen peroxide or resveratrol on this system was investigated, indicating a 7.4 × 10−11 mol/L of detection limit for H2O2 and 8.8 × 10−8 mol/L for resveratrol. The system was successfully employed to value the gross activity of antioxidants of peanut using resveratrol as the index. The results suggested a good recovery within the range from 88.8% to 109.1%.