Amperometric determination of chemical oxygen demand with flow injection analysis using F-PbO₂ modified electrode

An electrochemical detection system with an F-PbO₂ modified electrode for flow injection analysis to determine chemical oxygen demand (COD) was proposed and experimentally validated. The measuring principle was based on the current response on the modified electrode which was proportional to the COD value. Under the optimized experiment condition, the linear range was 100-1200 mg l^-1, and the detection limit was 15 mg l^-1. This method was successfully applied to determine the COD in samples without pretreatment. It was characterized by short analysis time, simplicity, low environmental impact, a limited reagent consumption and easy automation. Additionally, the COD values obtained from the proposed and conventional methods agreed well as demonstrated by the high significant correlation between the two sets of COD values (R = 0.9985, n = 25).