Electronic Theses and Dissertations

Date

2023

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Chemistry

Committee Chair

Paul Simone

Committee Member

Gary L Emmert

Committee Member

Michael A Brown

Committee Member

Charles Garner

Committee Member

Xiaohua Huang

Abstract

This dissertation includes the discussion on the development and optimization of three methods for the determination of haloacetic acids (HAAs) concentrations in drinking water and bulk sodium hypochlorite solutions. Additionally, an evaluation of a redesign for the Haloacetic Acid Rapid-Response (HAA-RR) system to reduce the size and cost while maintaining the same analytical performance as previous systems is discussed. To better understand the formation of haloacetic acids (HAAs) in drinking water, knowing when formation begins is important in minimizing the concentration in the final product. Assessing the bulk sodium hypochlorite solutions used to disinfect drinking water for HAA concentrations will determine if the HAA formation begins before or after dosing the bulk sodium hypochlorite solution into the water. However, sodium hypochlorite solutions have a complex matrix that interferes with many traditional testing methods. Establishing a distillation pretreatment step prior to analysis improves the effects of the matrix on the measurement. Distillation was paired with an ultra-pressure liquid chromatography-tandem mass spectrometry method, gas chromatography with electron capture detection method, and a post-column reaction ion chromatography method. Treated sodium hypochlorite solution and spiked recovery studies were run to assess HAA concentrations quantitatively and qualitatively in sodium hypochlorite solutions while testing the validity of the methods. The HAA-RR system is an excellent tool to help water treatment plant operators have access to near real-time haloacetic acid concentrations in their finished drinking water. Reducing the cost and size of the HAA-RR system will allow most WTPs to have the opportunity to monitor for HAAs. The system was redesigned by adapting the existing component into a “tower” enclosure and by using a high-pressure ion chromatography pump for delivery of fluorescent post-column reagents. To evaluate the analytical performance of the revised system, accuracy, precision, and method detection limit studies were performed and comparable results to previous systems were obtained.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to ProQuest.

Notes

Open Access

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