Chemical oxygen demand detection method research and portable instrument development based on microfluidic chip

Abstract

This paper presents a novel portable chemical oxygen demand (COD) detection method and instrument design based on the microfluidic chip technology. The oxidation reaction and temperature detection are integrated in a microfluidic chip. The principle is that there is heat released during the oxidation of organic compounds and the heat is proportional to the amount of organic compounds contained in water sample. The heat variation can be converted to voltage signal which has linear relationship with COD value. In this research, the NaClO solution is employed as oxidizer and the glucose solution is served as analyte. Three different geometric microfluidic chips are designed in order to choose the most suitable microfluidic chip scheme, the oxidizer concentration and injection rates. The flows characteristics, mixing behavior and heat release of fluids within the microfluidic chip are simulated and investigated by COMSOL multi-physics simulation software. The results show that the most suitable NaClO concentration, injection rates and microfluidic chip scheme are 28mol/L, lmm/s and Y sharp with block. A portable COD detection instrument based on the microfluidic chip technology is developed. There is a simple experiment for proving the feasibility of the instrument, the experiment results show that the experiment device is work well.