Water reclamation is one of the basic functions of the closed regenerative life support systems needed for manned space missions. To assure the quality of the recycled water, particularly for human consumption, monitoring of key water quality parameters, such as total organic carbon (TOC), pH, and conductivity is critical. TOC instruments are used to assess the levels of organic contaminants present in recycled water. NASA seeks for significant improvements in miniaturization, accuracy, precision, and operational reliability, as well as long life, real-time measurement, in-line operation, self-calibration, reduction of expendables, low energy consumption, and minimal maintenance for those monitors. Current available TOC analyzers do not meet those standards. This proposal concerns the development of a small, effective, energy-efficient, reagentless carbon analyzer (RCA). It will combine (i) electrochemical technology to produce two key elements in TOC analysis, acid and oxidant, and (ii) photolysis for the complete oxidation of organic carbons to carbon dioxide. It will also incorporate a microfluidic design. During the Phase I effort, the feasibility of the proposed system will be demonstrated. During the Phase II project, a microgravity-compatible, automated system will be fabricated and delivered to NASA.