An optrode type sensor to measure dissolved oxygen in water

Oxygen concentration in water is an important parameter in several industrial processes, for instance, in water treatment plants or in fish-farms. Electrochemical sensors provide a simple way to determine the oxygen concentration. However, these sensors present important drifts and they need continuous maintenance. Optical sensors are suitable for long term measurements. Most of the optical sensors are based on the measurement of fluorescence lifetimes or fluorescence intensities. In this paper, we present a fiber-optic oxygen sensor based on the measurement of phosphorescence lifetime of Al-Ferron in Sol-gel support. A silicone and nylon membrane is used to separate the sensor from the water. Sterm-Volmer ratio is used to determine the oxygen concentration.