Since oxygen is involved in most of the biological and chemical processes in aquatic environments, it is one of the most important parameters to be measured. Oxygen can also be used as a tracer in Oceangraphic studies. For environmental reasons it is critical to monitor oxygen in areas where the supply of oxygen is limited compared to demand,

The Aanderaa oxygen optodes are based on the ability of selected substances to act as dynamic fluorescence quenchers. The fluorescent indicator is a special platinum porphyrin complex embedded in a gas permeable foil that is exposed to the surrounding water. A black optical isolation coating protects the complex from sunlight and fluorescent particles in the water. This sensing foil is attached to a window providing
optical access for the measuring system from inside a watertight housing. The foil is excited by modulated blue light, and the phase of a returned red light is measured. By linearizing and temperature compensating, with an incorporated temperature sensor, the absolute O2
concentration can be determined.

Aanderaa Dissolved Oxygen features.

• • Response time <8 sec (63%)

• • High accuracy

• • Not stirring sensitive (it consumes no oxygen)

• • Lower fouling sensitivity

• • Measures absolute oxygen concentrations without repeated calibrations

• • Better long-term stability

• • Hot water monitoring

• • Less affected by pressure

• • Not sensitive to H₂S

• • Not freezing sensitive

*Only use 4330F if fast response oxygen, and/or fast response temperature is needed. The standard sensing foil is protected by an optical isolation layer which makes the foil extra rugged and insensitive to direct sunlight. The fast response sensing foil is not equipped with this layer; ambient light intensity higher than 15000 lux may cause erroneous readings. To avoid potential bleaching the fast response foil should be protected from ambient light when storing the sensor. We recommend the standard foil in applications where fast response time is not needed.

**Please note: All sensors use RS-232 for configuration.