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
- H2 production from water splitting
- Effect of H2 enriched drinking water
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.
|Standard Glass Sensor||Outside tip diameter|
|H2-500LR||400-600 µm - for low concentration range applications|
|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.