oxygen microsensor

dissolved & atmospheric oxygen


The Unisense oxygen microsensor is an excellent research tool for high quality oxygen measurements.

The microsensor can be made with tip sizes of only 2-3 µm allowing for non-destructive measurements of oxygen at high spatial resolution in numerous applications. The response time can be less than 0.3 sec and the oxygen microsensor has an insignificant oxygen consumption giving you fast and accurate oxygen measurements.

The Unisense oxygen microsensor has been used by the world’s leading scientists for decades and is cited in over hundreds of papers in journals such as Nature and Science.


  • Measurement tip size as small as 2 µm
  • Extremely fast T90 response times of less than 0.3 seconds
  • Suitable for a wide range of applications from biogeochemistry to biomedical


detailed information

Oxygen MicrosensorThe oxygen micro- and minisensors are all Clark-type sensors measuring oxygen partial pressure. The working principle of the oxygen microsensor is based on diffusion of oxygen through a silicone membrane to an oxygen reducing cathode. The reducing cathode is polarized against an internal Ag/AgCl anode.

The oxygen microsensor has a guard cathode that removes oxygen in the electrolyte, thus minimizing zero-current and pre-polarization time. The resulting sensor signal is in the pA range and is measured by a high quality picoammeter e.g. the Unisense Microsensor Multimeter.


tip diameter sizes
  • OX-10: 8-12 µm
  • OX-25: 20-30 µm
  • OX-50: 40-60 µm
  • OX-100: 90-110 µm
  • OX-500: 400-600 µm
  • OX-MR: 400-600 µm
  • OX-N: 1.1 mm
  • OX-NP: 1.6 x 40 mm – needle sensor for piercing
  • OX-Eddy: 90-110 µm – Fast sensor





Revsbech,N.P. (1989), An oxygen microsensor with a guard cathode, Limnol Oceanography, 474 – 478, vol. 34

Lackner,S. et al (2010), Nitritation Performance in Membrane Aerated Biofilm Reactors differs from conventional Biofilm Systems, Water Research, – , vol.

Lecoq,J. et al (2009), Odor-Evoked Oxygen Consumption by Action Potential and Synaptic Transmission in the Olfactory Bulb, Journal of Neuroscience, 1424 – 1433, vol. 29


manual & docs

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