Electronic Theses and Dissertations

Identifier

1295

Date

2014

Document Type

Dissertation (Access Restricted)

Degree Name

Doctor of Philosophy

Major

Chemistry

Concentration

Analytical Chemistry

Committee Chair

Gary L Emmert

Committee Member

Paul S Simone

Committee Member

Nathan J DeYonker

Committee Member

Randy K Buddington

Abstract

Haloacetic acids (HAAs) are a class of chlorinated disinfection by-products produces during the chlorination of drinking water. HAAs have potentially adverse health effects and are regulated by the USEPA at a maximum contaminant level of 0.060 mg L-1. Post-column reaction-ion chromatography with nicotinamide fluorescence (PCR-IC) was developed for analysis of HAAs in drinking water. The PCR-IC analyzer has two forms of selectivity toward the HAAs, and originally had method detection limit (MDL) values between 1 - 10 µg L-1.A sequential injection analysis (SIA) module has been developed for fully automated preconcentration of HAAs prior to analysis by PCR-IC--the SIA-PCR-IC. Preconcentration is achieved by solid phase extraction with a resin designed for environmental analysis. Optimization of method parameters was carried out, along with detailed MDL, accuracy, precision, and linearity studies; individual MDL values were all less than 1µg L-1. Side-by-side comparison studies of HAAs in real-world drinking water samples were also performed, comparing the optimized SIA-PCR-IC method with USEPA Method 552.3. Trace levels of HAAs detected in samples are reported, and bias values calculated between the two methods are less than 10µg L-1 for eight of the nine individual HAAs.In addition to studies focused on their formation in drinking water, HAAs research has recently branched out to investigate their presence in hypochlorite solutions used for drinking water disinfection. In response to previous work resulting in the detection of HAAs in over 30 different samples of hypochlorite, the PCR-IC analyzer and USEPA 552.3 were utilized to develop and apply a model for determining the contribution of HAAs detected in hypochlorite to those measured in finished water--the Dose-Dilution Model. Application of this model to eight different utilities resulted in an average contribution of about 40%.In order to gain more knowledge about the behavior of HAAs detected in hypochlorite solutions, studies were developed to monitor their formation and stability using the PCR-IC; short- and long-term storage temperature conditions were varied, while monitoring HAAs. Results suggest that HAAs formation occurs immediately following hypochlorite generation, while degradation was observed over time at various rates depending on strength and storage temperature.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.

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