Development and testing of a high sensitivity monitor for the measurement of Total Organic Carbon (TOC) in water without gravity-dependent components and using minimal chemical reagents has been performed. A breadboard instrument was constructed and tested for linearity, selectivity, and day-to-day reproducibility. The instrument has a linear response for a wide range of organic compounds over a range from 20 ppb C to 50 ppm C, with excellent day-to-day reproducibility. The upper level can be extended to ∼100 ppm C by changing the operating conditions of the analyzer. The selectivity of the instrument has been determined and no interference is observed except for high concentrations (> 10 ppm) of iodine, hypochlorous acid, sodium nitrite and sodium sulfide.Research into the development of a “reagentless” oxidation reactor based on a combination of electrolysis and UV photolysis has shown that high conversion efficiencies for the oxidation of methanol can be obtained at concentrations as great as 40 ppm C, and with further development, this technology should provide an attractive alternative to systems employing chemical oxidizing agents.