Assessing The Reactivity Of Amino Acids To Chlorination Using Capillary Electrophoresis

Author

Pedro De AllendeFollow

Date of Award

8-2024

Document Type

Thesis

Degree Name

Master of Science in Environmental Sciences

Department

Chemistry and Biochemistry

First Reader/Committee Chair

Brett Stanley

Abstract

Amino acids (AA) are ubiquitous in wastewater systems. One of the most popular wastewater treatments is chlorination which is effective at eradicating bacteria and overall treating the wastewater, but it can also produce disinfection by-products (DBPs). Certain DBPs have been classified as Class B Carcinogens to humans and are therefore highly regulated and monitored. Past studies have shown that natural organic matter (NOM), specifically amino acids, can be precursors to DBPs if chlorinated to the correct dose. This thesis project explored AA chlorination's mechanism(s) to understand further which products arise. In particular, the investigation detailed which steps of the mechanism vary depending on the amino acid and the chlorine dose, and which different DBPs are produced. Capillary electrophoresis (CE) will provide a different viewpoint. The hypothesis is that CE can detect DBP ions due to their detection based on electrophoretic mobility. Insight into the reactivity of individual amino acids undergoing chlorination will help understand their reactivity in mixtures and further guide the development of effective water treatment practices. From the experiments, what has been proven is that CE can track an AA chlorination reaction, and it can detect the DBP ion products. The experiments found the proposed DBP ions to have migration times between 4.73 and 8.55 minutes. Throughout the reaction, the product peak was shown to decrease in size for all AAs except for Glutamic Acid, Aspartic Acid, Lysine, and Proline during the 0.5:1 reactions. During the 1:1 reactions, the same is true but Serine also has a non-reacting product peak. Based on the different products seen in each of the doses it can be surmised that each amino acid will react differently to the Cl₂ depending on what dose is injected. To further delineate the identity of the DBP ions, Mass Spectroscopy will be used in a future study.

Recommended Citation

De Allende, Pedro, "Assessing The Reactivity Of Amino Acids To Chlorination Using Capillary Electrophoresis" (2024). Electronic Theses, Projects, and Dissertations. 1988.
https://scholarworks.lib.csusb.edu/etd/1988