Electronic Theses and Dissertations

Identifier

927

Date

2013

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, Jr

Committee Member

Charles Edwin Webster

Committee Member

Firouzeh Sabir

Abstract

Three separate analytical methods have been developed for application in the National Aeronautics and Space Administration’s water recovery initiatives on-orbit. Two methods have immediate impact to these initiatives while the third expands methodologies that are of interest to water quality monitoring. The first method has been developed for monitoring water disinfectants silver ion (Ag+) and iodine (I2), separately, using a single flow injection manifold. The estimated MDL values for Ag+ and I2 are 52 µg L–1 Ag+ and 2 µg L–1 I2; the mean percent recovery were 104% and 96.2% for Ag+ and I2 respectfully; and percent relative standard deviations were estimated at 1.4% for Ag+and 5.7% for I2. Sample analysis was evaluated for each respective disinfectant and compared to the standard methods of detecting Ag+ or I2, atomic absorption spectroscopy and a spectrophotometric leuco crystal violet method, respectively. The bias estimates compared to the reference methods were 11.3 µg L–1 Ag+ and 27.3 µg L–1 I2, in the same order. The second method utilized Nafion membrane in a capillary membrane sampler (CMS) device for sampling calcium ion (Ca2+) from raw and pretreated (sulfuric or phosphoric acid and hexavalent chromium dosed) urine prior to electrochemical detection. After optimization, the MDL, accuracy and precision measurements gave estimates at 2 mg L–1 Ca2+, 77% and 2.8% respectively. Standard addition has been used to minimize matrix effects found during sampling analysis of raw and pretreated urine. These results were compared to an ion chromatography method and reported Ca2+ biases of 6.6 mg L–1 (raw) and –59.9 mg L–1 (sulfuric dosed) and –19.1 mg L–1 (phosphoric dosed). The third project focused on developing a liquid-liquid microextraction with preconcentration method for haloacetic acid (HAA) analysis prior to separation using capillary electrophoresis with internal standardization. This method reported MDL estimates of 1.7–9.5 µg L–1 for the nine most common HAAs, a major class of disinfection by-product in drinking water. The results from HAA analysis of commercial bottled water demonstrated bias estimates compared to post column reaction-ion chromatography for HAAs averaged -0.11 µg L–1.

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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