N2O microsensor

dissolved & atmospheric nitrous oxide


The Unisense N2O microsensor is a unique sensor offering the possibility of measuring dissolved and gaseous N2O. With a detection limit of less than 0.5 µM and tip sizes down to 25 µm, the Unisense N2O microsensor is a high quality research tool for reliable and fast measurements.

The Unisense N2O microsensor is the only sensor available to measure N2O, as a greenhouse gas, for the wastewater industry. The Unisense N2O microsensor has been specifically designed for the wastewater industry.


  • Measurement tip size as small as 25 µm
  • Extremely fast T90 response times of less than 3 seconds
  • Suitable for a wide range of applications from wastewater to biogeochemistry to biomedical


detailed information

Unisense N2O-RThe Unisense nitrous oxide microsensor is a miniaturized Clark-type sensor with an internal reference and a guard cathode.

In addition, the sensor is equipped with an oxygen front guard, which prevents oxygen from interfering with the nitrous oxide measurements.

The sensor is connected to a high-sensitivity picoammeter and the cathode is polarized against the internal reference. Driven by the external partial pressure, nitrous oxide from the environment will penetrate through the sensor tip membrane and be reduced at the metal cathode surface. The picoammeter converts the resulting current to a signal. The internal guard cathode is also polarized and scavenges N2O in the electrolyte, thus minimizing zero-current and polarization time.

For special applications, some versions of the N2O microsensor can be customized to have extremely high sensitivity (25 nM). Please view specifications.


tip diameter sizes
  • N2O-25: 20-30 µm
  • N2O-50: 40-60 µm
  • N2O-100: 90-110 µm
  • N2O-500: 400-600 µm
  • N2O-R: Mounted cap
  • N2O-MR: 400-600 µm
  • N2O-N: 1.6 x 40 mm
  • N2O-NP: 1.6 x 40 mm – needle sensor for piercing





Andersen,K. et al (2001), An oxygen insensitive microsensor for nitrous oxide, Sensors and Actuators B-Chemical, 42 – 48, vol. 81

Elberling,B. et al (2010), High nitrous oxide production from thawing permafrost, Nature Geoscience, 332 – 335, vol. 3

Horn,M. et al (2003), The Earthworm Gut: an Ideal Habitat for Ingested N20-Producing Microorganisms, Applied and Environmental microbiology, 1662 – 1669, vol. 69

Kampschreur,M.J. et al (2008), Dynamics of nitric oxide and nitrous oxide emission during full-scale reject water treatment, Water Research, 812 – 826, vol. 42

Liengaard L, et al (2013) Extreme emission of N2O from tropical wetland soil (Pantanal, South America). Frontiers in Microbiology.  3:433. doi: 10.3389/fmicb.2012.00433

Zhou,Y. et al (2008), Development of a 2-sludge, 3-stage system for nitrogen and phosphorous removal from nutrient-rich wastewater using granular sludge and biofilms, Water Research, 3207 – 3217, vol. 42


manual & docs

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