(644b) Detection of Disinfection by-Products In Drinking Water Systems Via Biomimetic Metabolism

Disinfection by-products (DBPs) are generated by the reaction of disinfectants (e.g. chlorine) with natural organic matter present during drinking water treatment. DBPs metabolize in the body to form reactive intermediates which can be carcinogenic, genotoxic and hepatotoxic. The United States Environmental Protection Agency (US EPA) has established regulations for this type of compounds including trihalomethanes (THMs), haloacetic acids (HAAs), bromate and chlorite. However, emerging DBPs such as haloacetonitriles (HAN) have been found to be more toxic than their counterparts are. Real-time detection systems are essential for water distribution facilities to maintain public health and safety of potable water. While analytical techniques are frequently used offering selectivity and sensitivity, long processing times are seen as a drawback. On the other hand, biomimetic models offer long shelf-life and easy to use methods that have been developed in the prediction of drug metabolism. The purpose of this work is to develop an integrated biomimetic system for Phase I and II of metabolism monitoring glutathione (GSH) depletion. Assays of this kind can be utilized to screen for toxicity of samples by employing metalloporphyrins as structures that mimic the active site of cytochrome P450 offering the ability of detection of DBPs and anthropogenic compounds in drinking water systems. The aim of this presentation is to show the ability of biomimetic chemistry to generate in vivo metabolites of chloroform by optimizing variables such as pH, catalyst concentration, substrate concentration and oxidant while keeping temperature constant. Fourier Transform Infrared spectroscopy (FTIR) is used in Phase I of metabolism for the biomimetic reaction to monitor changes in absorbance for radical groups. Phase II of metabolism is carried out by GSH conjugation of metabolites generated in Phase I in the presence of cetyltrimethylammonium bromide (CTAB), catalyst that mimics the role of glutathione transferase (GST) in the detoxification step. CTAB is a cationic surfactant that reduces the surface tension of water inducing the formation of micelles. Critical micelle concentration determination ensures that the right concentration is in use in the optimization of Phase II of metabolism. Future work includes the application of electrochemical methods to determine GSH depletion in the integrated biomimetic chemistry Phase I and II.