The development and optimization of techniques for monitoring water quality on-board spacecraft using colorimetric solid-phase extraction (C-SPE)

Date
2007-01-01
Authors
Hill, April
Major Professor
Advisor
Marc D. Porter
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Altmetrics
Authors
Research Projects
Organizational Units
Chemistry
Organizational Unit
Journal Issue
Series
Department
Chemistry
Abstract

Manned missions to the moon, Mars, and deep space are currently a top priority for NASA. However, the lack of technology capable of maintaining and monitoring a life support system for long-term spaceflight presents many significant challenges. Moreover, recent issues with potable water quality on-board the International Space Station (ISS) have underscored the need to develop techniques for monitoring water quality in flight. This dissertation focuses on the development and microgravity validation of colorimetric-solid phase extraction (C-SPE) technology for the in-flight monitoring of spacecraft water quality. C-SPE measures the change in the diffuse reflectance of indicator disks following exposure to a water sample. A typical C-SPE analysis can be performed in ∼2 min and requires only small, easy-to-use, lightweight hardware.;Specifically, this dissertation describes the development of C-SPE methods for determining formaldehyde and total silver. Formaldehyde is a contaminant that has recently been detected in the drinking water supplies on-board NASA spacecraft, while silver is currently used as a biocide to prevent microbial contamination of the ISS potable water supply. The formaldehyde method, which represents the first application of C-SPE to the detection of an organic analyte, can quantify formaldehyde concentrations from 0.08 to 20 ppm in ∼3 min using only ∼1 mL of sample. The total silver method builds on a C-SPE technique for detecting silver(I) that was previously developed in our laboratory. The new method determines the total concentration of silver (i.e., dissolved and colloidal) in the range of 0.1-1 ppm, which spans the ISS potable water target level of 0.3-0.5 ppm. This method also requires only ∼1 mL of water and can be completed in less than 3 min.;Included in the dissertation are the results of recent microgravity evaluations of C-SPE techniques on-board NASA's C-9 microgravity simulator. These experiments established effective methods for accurately collecting water samples of a target volume in microgravity, which had previously proven very problematic. Importantly, the flight results validated the performance of our C-SPE analyses for silver(I) and iodine (I2) under reduced gravity conditions, paving the way for a six-month technology demonstration project, scheduled on ISS for mid-2009.

Comments
Description
Keywords
Citation
Source