(606f) Non-Biological Inhibition Based Sensing (NIBS) for Detection of Trihalomethanes (THMs) in Drinking Water

The use of chlorine for disinfection is a very popular and effective method for drinking water treatment. The chlorine disinfectants are able to destroy waterborne pathogens and also protect drinking water from contamination during delivery to consumers. However, chlorine reacts with natural organic matter (NOM) and anthropogenic chemicals present in the water to form disinfection by-products (DBPs), such as trihalomethanes (THMs), which can be carcinogenic, genotoxic, cytotoxic, and hepatotoxic at moderate concentrations. Unfortunately, there are currently no “real-time” techniques available to monitor for low levels of THMs in finished drinking water.  Many drinking water treatment facilities must send samples to off-site laboratories in order to determine DBP concentrations.  This can create a delay in detection of up to 48 hours and result in the distribution of potentially toxic drinking water to consumers. Therefore developing a detection method that will rapidly sense low concentrations of regulated THMs in aqueous samples would help mitigate potential health concerns and increase the quality of water being delivered to consumers’ homes. Our solution is to develop a sensor that will provide a “real-time” detection of toxic THMs in drinking water. The chemistry for this sensor is based on a new technique in chemical amplification called non- inhibition based sensing (NIBS). In NIBS, instead of the analyte (THM) acting as a catalyst, the analyte rather acts as an inhibitor for the given reaction. The amount of the THM present in the reaction is then determined from the kinetics of the inhibited NIBS reaction. The catalyst solution for the reaction is prepared via Fujiwara reaction, where the THM (inhibitor) binds to the pyridine (catalyst). In this presentation, I will discuss the optimization of the Fujiwara reaction, which will comprise mainly of effects of temperature, residence time and NaOH/ pyridine ratio on Fujiwara reaction. Also, I will expound on the optimization of the catalytic reaction, which will include the effects of reactant concentrations and temperature on the catalytic reaction. Finally, I will demonstrate proof of NIBS concept by showing examples of inhibition versus concentration for the THMs (chloroform, bromoform, dichlorobromomethane and dibromochloromethane).