Oxygen Optode

Since oxygen is involved in most of the biological and chemical processes in aquatic environments, it is the single most important parameter needing to be measured. Oxygen can also be used as a tracer in oceanographic studies.


Oxygen Optodes is designed to measure absolute oxygen concentration and % saturation and are based on the ability of selected substances to act   as dynamic fluorescence quenchers. The fluorescent indicator is a special platinumporphyrin complex embedded in a gas permeable foil that is exposed to the surrounding water. The lifetime-based luminescence quenching principle offers the following advantages over electro-chemical sensors:

  • Optical measurement principle
  • Oxygen luminescence quenching principle
  • Non - invasive (no oxygen consumption)
  • Better long-term stability
  • High accuracy
  • Better long-term stability

  • Less affected by pressure

Principle of operation

The principle of measurement is based on the effect of dynamic luminescence quenching (lifetime based) by molecular oxygen. The sensing foil is excited by modulated blue light; the sensor measures the phase of the returned red light. For improved stability the optode also performes a reference phase reading by use of a red LED that do not produce fluorescence in the foil. The sensor has an incorporated temperature thermistor which enables linearization and temperature compensation of the phase measurements to provide the absolute O2-concentration.

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