Optical oxygen sensors have many advantages compared to commonly used measurment devices, like for example Clark-type electrodes. With optical oxygen sensors no electrolyte solutions are necessary and oxygen is not consumed in the measurement process. These sensors have excellent long term stability, are not influenced by the flow rate of samples, and can be used for measurements in liquid and gas phase. One of the major advantages of optical oxygen measurement is the possibility to determine oxygen concentrations non-invasively.
Working Principle
Optical oxygen sensors work according to the principle of dynamic fluorescence quenching. The sensors contain fluorescent dye that is excited by light of a certain wavelength. Depending on the amount of oxygen molecules present the luminescence response of the optical sensor varies. A polymer optical fiber transmits the excitation light of the sensor and at the same time also transmits the fluorescence response of the sensor to the measurement device. The optical fiber can, but does not have to be in contact with the sensor material which enables non-invasive measurement through transparent or semi-transparent vessel walls.
The oxygen sensitive dye is immobilized in a polymer matrix. This polymer can be applied to carrier material and used as sensor spots or sensor foil. It can also be coated directly onto the optical fiber.
The Ideal Oxygen Measurement System
The flexibility optical oxygen measurement offers seems endless. This measurement technique can be applied in many different ways and sensor shapes and housings can be adapted to almost any application.