H2 microsensor

dissolved hydrogen measurements


The Unisense hydrogen (H2) microsensor is an excellent research tool for high quality dissolved hydrogen measurements.

The microsensor can be made with tip sizes of only 2-3 µm allowing for non-destructive measurements of H2 at high spatial resolution in numerous applications. The response time can be less than 3 seconds and the H2 microsensor has an insignificant H2 consumption giving you fast and accurate H2 measurements.

The Unisense hydrogen 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 3 seconds
  • Suitable for a wide range of applications from biogeochemistry to biomedical


detailed information

PageLines-UnisenseOX-MR.jpgThe hydrogen micro- and minisensors are all Clark-type sensors measuring hydrogen partial pressure. The working principle of the hydrogen microsensor is based on diffusion of hydrogen through a silicone membrane to a hydrogen oxidizing platinum anode. The reducing anode is polarized against an internal Ag/AgCl cathode. The resulting sensor signal is in the pA range and is measured by a high quality picoammeter e.g. the Unisense Microsensor Multimeter.

As hydrogen concentrations found in natural systems are generally very low, a low detection limit of the sensor is important. Generally the detection limit of the sensors is close to 0,02% of hydrogen (0,1 µM in water) but it is possible to make all but H2-10 and H2-25 sensors even more sensitive if they are provided with a large tip membrane. However, such hypersensitive sensor suffers from a considerable stirring sensitivity (up to 25 %).


tip diameter sizes
  • H2-10: 8-12 µm
  • H2-25: 20-30 µm
  • H2-50: 40-60 µm
  • H2-100: 90-110 µm
  • H2-500: 400-600 µm
  • H2-MR: 400-600 µm
  • H2-N: 1.1 mm
  • H2-NP: 1.6 mm – needle sensor for piercing
  • H2-Eddy: 15-25 µm





Brand,A. et al (2007), Microsensor for in situ flow measurements in benthic boundary layers at submillimeter resolution with extremely slow flow, Limnology and Oceanography-Methods, 185 – 191, vol. 5

Kajiya,M. et al (2009), Hydrogen from intestinal bacteria is protective for Concanavalin A-induced hepatitis, Biochemical and Biophysical Research Communications, 316 – 321, vol. 386


manual & docs

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