SBIR Phase I: Supercritical Water Oxidation Based Dissolved Organic Carbon Analyzer

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This Small Business Innovation Research Phase I project focuses on the development of a Supercritical Water Oxidation (SCWO) based Total Organic Carbon (TOC) analyzer is proposed for the determination of Dissolved Organic Carbon (DOC) in seawater. The proposed innovation takes advantage of the unique chemical properties of supercritical water to achieve an extremely rigorous and thorough oxidation of complex organic substances. It is anticipated that this new methodology will provide chemical oceanographers with a useful alternative to current instrumental techniques. On occasion there has been relatively poor agreement among the DOC results derived by different measurement techniques when applied to seawater samples. Current analytical instruments for the determination of DOC in seawater suffer from inconsistent carbon recoveries, degradation of performance with time, calibration difficulties, and deleterious matrix effects. The SCWO based DOC analyzer (SCWO-DOC) is intended to provide a means for the mitigation of these difficulties. In principal, the SCWO-DOC analyzer utilizes oxygen saturated water which has been heated and pressurized to values greater than the respective critical points for the complete 'deep oxidation' or mineralization of dissolved organic molecules, resulting in the formation of inorganic species including: CO2, H20, NO3-, SO4=, and PO4-3. The CO2 is then removed in the vapor phase and quantified very accurately using a non-dispersive infrared (NDIR) detector. The proposed analyzer embodies a simple, reliable, reagentless, rapid, one step method of DOC determination with strong potential for extremely rigorous oxidation of refractory dissolved organics and with minimal susceptibility to interferences. The Phase I effort will demonstrate the feasibility of the concept for the analysis of seawater samples. It is anticipated that follow-on work at the Phase II level will culminate in the development and testing of a prototype which can be evaluated by members of the chemical oceanographic community. A more accurate and reliable instrumental means of determining total organic carbon (TOC) would find wide application throughout analytical chemistry. This new technology will be of particular interest in biotechnology, pharmaceutical, semiconductor, and oceanographic analytical applications which require quantitation of very low levels of un-characterized and often refractory dissolved organic substances.