Recently, chlorine-based disinfectants are increasingly in demand due to Corona virus. Consumer chemical products (CCPs) containing chlorine dioxide and sodium dichloroisocyanurate (NaDCC) have been widely used as an effective chlorine-based disinfectant. The reason for their usage is chlorine's effectiveness against most of the bacteria, while its harmless characteristics to human body. However, long-term consumption and exposure to the residual chlorine in water could damage the cell membrane and even DNA. Therefore, it is important to measure the exact concentration of residual chlorine in water sample and keep the concentration below residual level. One of the difficulities in measuring the concentration of chlorine species in water comes from their highly reactive characteristics. Aqueous chlorine species exist in various chemical structures like chlorine dioxide, hypochlorite and hypochlorous acids. Therefore, it is impossible to specifically measure certain type of chlroine species. Colorimetric measurement of chlorine using (DPD), or DPD method, has been the standard method for measuring the free chlorine in water sample. NaDCC has a special property. When it's dissociated in water, it exists in two states, HOCl and cyanuric acid. It is necessary to quantify the absorption intensity of cyanuric acid by maintaining a constant pH using an appropriate butter. We will use several spectrometers to find better analytical method for aqueous free chlorine species.

This work was supported by Korea Environment Industry & Technology Institute (KEITI) through Technology Development Project for Safety Management of Household Chemical Products, funded by Korea Ministry of Environment (MOE) (KEITI:2020002960003, NTIS:1485017121)