S13: Luminescent Dissolved Oxygen Probe with Unique Capabilities

We report on a novel luminescent dissolved oxygen probe with superior sensing film characteristics in aqueous media.  The optical sensor utilizes the ³O₂ quenching of the phosphorescence from MoCl indicators immobilized in a hydrophobic silicone matrix.  Reliable measurements for extended periods of time, months rather than weeks, were obtained in “open systems” such as aquaculture.  A “plug and play” module has been specifically developed for use in bioreactors.  We report on the probe performance in relation to “industry standard” technology based on studies of the spontaneous sustained metabolic oscillations in Saccharomyces cerevisiae.  The completely inorganic sensing film does not suffer from photobleaching and has a response that is specific to molecular oxygen in the presence of a host of common interferants including CO₂.  The accuracy of the probe was determined with respect to thermodynamics.  Competing oxygen sensing techniques can not simultaneously satisfy the requirements of sensitivity, accuracy, specificity and time response.  Our optical oxygen sensor provides a unique tool kit for dissolved oxygen monitoring in fermentation processes.