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%.