Application of fluorescence EEM-PARAFAC components to assess disinfection byproduct formation potentials

Disinfection byproduct formation potential (DBP FP) tests are conducted to assess the capacity to form DBPs in different water samples. During the DBP FP tests, quenching agents are used stop the reaction between the disinfectant and substances in the water matrix. Various quenching agents are used; however, not all are suitable. The quenching agent should act quickly and have minimal influence on measured DBP concentrations. Potential negative influences include the decay or formation of DBPs, reduced extraction efficiencies, or detection interference during DBP analysis. Additionally, DBP extraction is time-consuming, and the results are not immediately known. Recently, fluorescence spectroscopy via an excitation-emission matrix (EEM) has proven to be an effective online tool to characterize dissolved organic matter and interpret water quality. In particular, parallel factor analysis (PARAFAC) is proven to be an effective tool for extracting the EEMs information and identifying their behavior by tracing the individual water constituents and chemical composition. Commonly used quenching agents also impact the fluorescence EEMs by altering the optical properties of the samples. Results of this ongoing project will be shared for three objectives: 1) determination of the kinetics for common quenching agents, 2) assessment of the impact of the quenching agents on the fluorescence EEMs to understand the change in optical properties, and 3) correlation between the PARAFAC components and DBP FP. Ultimately, different constituents of organic matter that affect the DBP FPs can be better understood and further used as an online monitoring tool to assess DBP precursors in the distribution system.