What is the relationship between UV254 and TOC, COD?

Cod (chemical oxygen demand) TOC (total organic carbon)

     Organic pollutants in water have absorption peak at 254nm wavelength. After calibration, the absorption value of light intensity at this wavelength can best characterize the concentration of organic matter, and this value can be converted into COD by mathematical method. This method is simple, no reagent is required, and it is real-time measurement. However, the optical method also has some defects, that is, the requirement for water composition is relatively stable, Otherwise, the organic matter concentration can not be well reacted

In addition, we know that,

C+O2=CO2

C means organic matter. If we measure the content of organic matter, that is cod. If we measure CO2, that is TOC. That is to say, COD and TOC have a certain proportional relationship. This relationship depends on the carbon valence of the measured material. Therefore, TOC and COD can be transformed into each other under certain conditions