Optical Dissolved Oxygen Sensors

A METTLER TOLEDO optical dissolved oxygen sensor combines precise measurements with low maintenance to continuously monitor the dissolved oxygen level in water or another liquid. The heart of the optical DO sensor is an oxygen-sensitive layer containing immobilized marker molecules. They absorb light from a light emitting diode and are able to release this energy as light at a different wavelength (fluorescence). This effect allows determination of the oxygen concentration in the sample media. These optical dissolved oxygen probes offer highly accurate oxygen measurements with enhanced signal stability and fast response times. The sensors are fully steam sterilizable, autoclavable and fulfill requirements for hygienic design and traceability. Since no electrolyte exchange or sensor polarization is needed, sensor maintenance is easy and less error-prone. This optical dissolved oxygen probe also takes advantage of ISM technology.

METTLER TOLEDO offers a range of optical dissolved oxygen sensors fully suitable for diverse hygienic applications. The InPro 6860i optical DO probe offers highly accurate oxygen measurement with enhanced stability, and easy handling without electrolyte change or time-consuming polarization procedures in biopharma applications. The InPro 6960i/6970i optical DO probes provide outstanding measurement performance with a low detection limit, minimum drift and short response time to improve oxygen monitoring and reduce out of spec production. Optical oxygen technology in 12 mm design like the InPro 6960i/6970i is available for challenging brewery applications such as filler line measurement. For pure water monitoring, the Pure Water Optical DO Probe from METTLER TOLEDO Thornton offers fast response and increased stability in demanding low-ppb applications such as monitoring DO in microelectronics ultrapure water systems or power plant water.

METTLER TOLEDO offers two in-line dissolved oxygen sensors that utilize different technologies to determine dissolved oxygen levels in water or other liquids. Optical DO sensors utilize fluorescence quenching technology, which is the result of an energy transfer between a fluorescing chromophore and oxygen molecules. Polarographic dissolved oxygen sensors are membrane based and use polarographic technology. Oxygen diffuses through the membrane and is reduced at a cathode that is held at a defined potential. The measured reduction current is proportional to the partial pressure of oxygen in the media. Both optical DO sensors and polarographic DO sensors have a hygienic design and are available with Intelligent Sensor Management (ISM) predictive diagnostics.

With Intelligent Sensor Management (ISM), the installation, maintenance and safety of the optical DO sensor system improves significantly. All relevant data is stored in the sensor, and real-time diagnostics provide all necessary information for deciding if a sensor is good for the next batch. Plug and Measure technology in the optical dissolved oxygen sensor leads to faster start up, no configuration at the transmitter and the risk of handling errors is eliminated. The need for maintenance in the optical oxygen measuring system is monitored via the Dynamic Lifetime Indicator. With these features, error-free and safe operation of the optical dissolved oxygen probe is assured.