RELATIVE REACTIVITY OF SIX AMINO ACIDS WITH SODIUM HYPOCHLORITE MEASURED BY GAS CHROMATOGRAPHY/ MASS SPECTROMETRY AND METHYL CHLOROFORMATE DERIVATIZATION.

Author

Josephine Wangui GitauFollow

Date of Award

5-2023

Document Type

Thesis

Degree Name

Master of Science in Environmental Sciences

Department

Chemistry and Biochemistry

First Reader/Committee Chair

Stanley, Brett

Abstract

There are 20 common amino acids that act as building blocks for proteins and each one of them differ from each other due to their chemical structure of the R group. During the process of chlorination of water and wastewaters, amino acids present have been implicated as precursors of disinfection by-products. For the analysis of amino acids Gas Chromatography/Mass Spectrometry (GC/MS) is widely used. In this research six amino acids (glycine, valine, leucine, isoleucine, methionine, and phenylalanine) were derivatized with Methyl Chloroformate and analyzed using Gas Chromatography/Mass Spectrometry without heating. The main aim of this study was to observe the reaction of the six combined amino acids when sodium hypochlorite is added at different molar ratios of 0.5, 1.0, 2.0 and 3.0. Using Gas Chromatography/Mass Spectrometry analysis peak retention times and area was observed on the GC/MS instrument. While identifying their retention time we were able to observe whether their peak areas increase or decrease for each amino acid as compared to the previous research done. From the resulting peaks, we were able to determine the decrease of amino acids concentration when reacting with different amount of sodium hypochlorite a common disinfectant reagent. There was no observation made of chloroamino acids because they do not undergo analogous derivatization with methyl chloroformate or are thermally decomposed in the Gas Chromatography. There comparison was made on chlorinated reaction time set by stopping the reaction with dechlorinated agent sodium bisulfite (NaHSO₃) and the reaction was allowed to proceed without quenching with sodium bisulfite. The derivatization method used in this study was considered to not be the general method of measuring amino acids and disinfection by-products (DBPs) since only one disinfection by-product was observed.

Recommended Citation

Gitau, Josephine Wangui, "RELATIVE REACTIVITY OF SIX AMINO ACIDS WITH SODIUM HYPOCHLORITE MEASURED BY GAS CHROMATOGRAPHY/ MASS SPECTROMETRY AND METHYL CHLOROFORMATE DERIVATIZATION." (2023). Electronic Theses, Projects, and Dissertations. 1672.
https://scholarworks.lib.csusb.edu/etd/1672