You are here: Products bread Sensors and Electrodes bread H2 Microsensor

H2 Microsensor

Highly sensitive hydrogen microsensor

The Unisense hydrogen microsensor offers you extraordinary sensitivity allowing for reliable hydrogen measurement even in natural systems. The sensor is fast responding and the tip can be miniaturized down to 10 µm achieving high spatial resolution.

The design makes it possible to use the hydrogen microsensor in a broad variety of research fields where high quality, non-destructive, fast, and accurate measurements are required. The hydrogen microsensor is designed for research applications within:

  • Environmental sciences
  • Biomedical sciences
  • Biotechnology
  • H2 production from water splitting
  • Effect of H2 enriched drinking water

Microsensor technology

Unisense offers two types of hydrogen microsensors. The standard type, the H2-type, is for use in H2S free environments because H2S interferes with the H2 measurement. For use in H2S containing environments, the H2-X-type should be used. This sensor has an H2S guard in the sensor tip that makes it insensitive to H2S up to 100 µM H2S or 1000 ppm H2S in gas. It is possible to make sensors with an even higher tolerance to H2S. Contact Unisense for more information. 

The two types of hydrogen sensors, H2- and H2-X-type, are used in the same way. The only differences between the two sensor types are that the H2-X-type tolerates H2S and has a slightly slower response.

The H2 and H2-X microsensors are Clark-type sensors measuring hydrogen partial pressure. The working principle of the hydrogen microsensor is based on diffusion of hydrogen through a silicone rubber membrane in the tip to a platinum anode where the hydrogen gets oxidized. This anode is polarized against an internal reference electrode which receives the electrons from the oxidation of hydrogen at the platinum anode. The resulting current changes linearly with the hydrogen concentration at the sensor tip and is in the pA range. It is measured by a high quality picoammeter e.g., the Unisense UniAmp amplifiers. 

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 0.04% of hydrogen (0.3 µM in water) but it is possible to make the sensors even more sensitive if they are made with a larger tip membrane, except for those with 10 µm and 25 µm tip diameter. Such low range sensors are more sensitive to stirring due to the larger analyte consumption rate. The H2-type sensor can even be produced with an extreme sensitivity with a detection limit lower than 10 nM dissolved (approx. 0.00125%) H2. And as for all Unisense sensors, the H2 sensors can also be made for much higher H2 concentrations in pressurized systems. 

Ordering Information

Standard Glass Sensor Outside tip diameter
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
H2-500LR 400-600 µm - for low concentration range applications
H2-MR 400-600 µm
H2-N 1,1 x 40 mm - needle sensor
H2-NP 1,6 x 40 mm - needle sensor for piercing
H2-NPLR 1,6 x 40 mm - needle sensor for piercing and for low concentration range
H2-X-50 40-60 µm, H2S insensitive
H2-X-100 90-110 µm, H2S insensitive
H2-X-500 400-600 µm, H2S insensitive
H2-X-MR 400-600 µm, H2S insensitive
H2-X-100LR 90-110 µm, H2S insensitive - for low concentration range applications
H2-X-500LR 400-600 µm, H2S insensitive - for low concentration range applications
H2-X-MRLR 400-600 µm, H2S insensitive - for low concentration range applications
H2-X-NP 1,6 x 40 mm, H2S insensitive - needle sensor for piercing
H2-X-NPLR 1,6 x 40 mm, H2S insensitive - needle sensor for piercing and for low concentration range

Find complete hydrogen microsensor specifications, including warranty and expected life time, below and possible microsensor customizations and adaptations under Related Products found to the right.

View H2 Microsensor Specifications

Technical information

View H2 sensor specifications

Technical information

View H2-X sensor specifications

Related products

Sensor Customization

Sick, Torben et al (2018), Oriented Films of Conjugated 2D Covalent Organic Frameworks as Photocathodes for Water Splitting, Journal of the American Chemical Society, 2085 - 2092, vol. 140 Read abstract

Sherman, Benjamin D. et al (2016), A Dye-Sensitized Photoelectrochemical Tandem Cell for Light Driven Hydrogen Production from Water, Journal of the American Chemical Society, 16745 - 16753, vol. 138 Read abstract

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

Brand, Andreas 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

See all publications
Unisense user workshop

Unisense user workshop

Do you want to learn more about microsensors? We invite customers to join one of our user workshops here at Unisense. The program is a mix of theoretical lectures and hands-on experiments.

Read more