Using Electrochemistry - Total Internal Reflection Imaging Ellipsometry to Monitor Biochemical Oxygen Demand on the Surface Tethered Polyelectrolyte Modified Electrode

摘要

Our previous work has proposed an electrochemistry - total internal reflection imaging ellipsometry (EC-TIRIE) technique to observe the dissolved oxygen (DO) reduction on Clark electrode since high interface sensitivity makes TIRIE a useful tool to study redox reactions on the electrode surface. To amplify the optical signal noise ratio (OSNR), a surface tethered weak polyelectrolyte, carboxylated poly(oligo(ethylene glycol) methacrylate-random-2-hydroxyethylmethacrylate) (abbreviated as carboxylated poly(OEGMA-r-HEMA)), has been introduced on the electrode surface. Since Clark electrode is widely used in biochemical oxygen demand (BOD) detection, we use this technique to measure BOD in the sample. The dynamic range of the system is from 0 ～ 25 mg/L. Two samples have been measured. Compared with the conventional method, the deviation of both optical and electrical signals are less than 10%.