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Potable and hygiene water availability is a critical requirement for long-duration manned space missions. Frequent water quality testing helps to ensure astronaut health by providing needed feedback on the effectiveness of on-board water purification units. One of the most basic and broad-spectrum indicators of contamination is organic carbon concentration. To meet the need for water quality feedback on the International Space Station (ISS), as well as on planned missions to Luna and Mars, Lynntech is developing a mesofluidic total organic carbon analyzer (TOCA) through the NASA SBIR program. The unit has been designed to operate in the demanding environment of a long-duration manned space mission and addresses the issues of microgravity operation, an operating lifetime of 5 years, low power consumption, simple user interface, robust architecture, and inherent safety.

The development of a new microfluidics based carbon analyzer that is capable of generating chemicals needed in the analysis is described. The analyzer design is based on several components, an electrochemical cell, a membrane conductivity sensor, and an electrochemical water de-ionizer, which utilize porous membranes such as proton exchange membrane, gas separation membrane, and ion exchange membrane n their operation. These membrane-based microfluidic devices (MBMD) allow miniaturization of the carbon analyzer into a compact instrument which will provide high sensitivity and low power consumption. Each of the membrane-based microfluidic components was fabricated and their functioning tested over a broad range of inorganic or organic carbon content in water samples.

Electrochemical oxidant generation has been combined with UV photolysis to provide a highly effective means of water purification, decomposition of bacterial organic substances, microbiological control and sterilization. Ozone is an oxidant with many unique features that make it a valuable tool for biomedical applications. It is an excellent bactericidal, virucidal and sporicidal agent making it ideal for use as a sterilant. Combining O3 with UV radiation stimulates formation of hydroxyl radicals (OH·) which accelerates a wide range of organic oxidations. While in some instances maintenance of an oxidant residual is necessary, the residual can be rapidly removed by UV light at the point of use (i.e., Water For Injection). Test results on pyrogen decomposition, bacterial organic decomposition, microbiological sterilization, residual removal and water purification as a final step for producing pharmaceutical grade water are discussed.