OX-25_1400x800
Needle sensor_700x400
OX-NP_700x400
OX-NP tip_700x400
O2 UniAmp_700x400
fx-6 UniAmp
Designed for research applications within:
Environmental Sciences
Biomedical Sciences
Biotechnology
Microbiology

O2 Microsensor

High performance O2 microsensor

With tip sizes of only 2-3 µm, you can measure oxygen at high spatial resolution without damaging your sample. You can choose a response time of less than 0.3 sec and attain fast and accurate oxygen measurements thanks to the insignificant oxygen consumption. Read more...

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Technical Data
Ordering Information & Sizes
Adaptations
Manuals & Videos
O2 Microsensor

Oxygen microsensor principle

The O2 microsensors are all Clark-type sensors measuring oxygen partial pressures. 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 O2 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, such as the UniAmp Multi Channel.

OX-500 sensor tip_1400x800
General
Cables & Connectors
Characteristics
Stirring Sensitivity & Response Time
General
Feature Standard Options Extra price for option selection
Feature
Total length
Standard
150-200 mm
Options
70-350 mm
Extra price for option selection
10-50%
Feature
Diameter 20 mm from tip
Standard
< 2 mm
Options
< 1 mm
Extra price for option selection
10%
Feature
Diameter 50 mm from tip
Standard
8 mm
Options
< 2 mm
Extra price for option selection
20%
Feature
Glass shaft diameter
Standard
8 mm
Options
6-20 mm
Extra price for option selection
20%
Feature
Plastic shaft protection diameter*
Standard
11 mm
Options
Can be omitted
Extra price for option selection

*When mounted with in situ mini connectors, the shaft has no protection mounted, but fits directly into the in situ sensor mounts with pressure compensation. In situ sensors have a standard length of 130-160 mm.

Cables & Connectors
Item Standard Options Extra price for option selection
Item
Cable
Standard
Habia
Item
Cable length
Standard
1.5-2 m
Options
0-10 m
Extra price for option selection
Yes, depends on length
Item
Connector
Standard
LEMO
Options
BNC adapter
Extra price for option selection
Yes, order separately
Item
In situ gold pin connector*
Standard
No
Options
Yes

*When mounted with in situ mini connectors, the shaft has no protection mounted, but fits directly into the in situ sensor mounts with pressure compensation. In situ sensors have a standard length of 130-160 mm.

Characteristics
Attribute Standard Options Extra price for option selection
Attribute
Guaranteed lifetime
Standard
6 months (modifications not included)
Attribute
Guaranteed lifetime OX-Eddy
Standard
2 months
Attribute
Expected lifetime
Standard
> 1 year*
Attribute
Temperature range
Standard
-10-60°C
Attribute
Temperature range tip
Standard
-10-60°C (not needle versions)
Options
-10-90°C (organic electrolyte - not needle versions)
Extra price for option selection
20%
Attribute
Temperature coefficient
Standard
2-3% per °C
Attribute
Range
Standard
About 0-1 atm pO2
Options
Optimization of high range
Attribute
Detection limit
Standard
0.3 µM
Options
0.050 µM
Extra price for option selection
10%
Attribute
Internal guard
Standard
Yes
Options
Can be omitted
Attribute
Waterproof
Standard
Yes
Attribute
Pressure tolerant sensing tip
Standard
Yes
Attribute
Tip colour
Standard
Glass
Options
Black painted
Extra price for option selection
Contact Unisense
Attribute
Electrolyte with fluorescein (fluorescent)
Standard
No
Options
Yes
Extra price for option selection
10%
Attribute
Spatial resolution
Standard
Equals outside tip diameter
Attribute
Response
Standard
Linear
Attribute
Sensor oxygen consumption
Standard
2.5-25.0 x 10-10 mg O2/min equals approx. 4*10-4 - 5*10-3 nmol/hour

*Shorter lifetime may be experienced for oxygen sensors with tip diameter of 10µm (OX10) including the OX-Eddy microsensor.

Stirring Sensitivity & Response Time
Item Stirring sensitivity Response time (90%) Extra Price
Item
OX-10 standard
Stirring sensitivity
< 2%
Response time (90%)
1-3 s
Extra Price
-
Item
OX-10 fast
Stirring sensitivity
< 5%
Response time (90%)
< 0.3 s
Extra Price
15%
Item
OX-25 standard
Stirring sensitivity
< 2%
Response time (90%)
< 4 s
Extra Price
Item
OX-25 fast
Stirring sensitivity
< 5%
Response time (90%)
< 0.5 s
Extra Price
15%
Item
OX-50 standard
Stirring sensitivity
< 2%
Response time (90%)
< 5 s
Extra Price
Item
OX-50 fast
Stirring sensitivity
< 5%
Response time (90%)
< 1 s
Extra Price
15%
Item
OX-100 standard
Stirring sensitivity
1.5%
Response time (90%)
< 8 s
Extra Price
-
Item
OX-100 fast
Stirring sensitivity
5%
Response time (90%)
< 2 s
Extra Price
15%
Item
OX-200 standard
Stirring sensitivity
< 1.5%
Response time (90%)
< 8 s
Extra Price
-
Item
OX-500 and OX-MR standard
Stirring sensitivity
1.5%
Response time (90%)
< 15 s
Extra Price
Item
OX-500 and OX-MR fast
Stirring sensitivity
< 5%
Response time (90%)
< 3 s
Extra Price
15%
Item
OX-Eddy Standard 150-200 µm
Stirring sensitivity
< 1%
Response time (90%)
< 0.4 s
Extra Price
Item
OX-Eddy 40-60 µm
Stirring sensitivity
1%
Response time (90%)
< 0.3 s
Extra Price
Item
OX-Eddy 90-100 µm
Stirring sensitivity
1%
Response time (90%)
< 0.4 s
Extra Price
Item
OX-N exposed tip
Stirring sensitivity
< 2%
Response time (90%)
< 10 s
Extra Price
Ordering information & Sizes
Ordering information & Sizes
Oxygen Sensor Size and description Options Extra price for option selection
Oxygen Sensor
OX-10*
Size and description
8-12 µm - glass sensor
Options
3-5 µm
Extra price for option selection
20%
Oxygen Sensor
OX-25
Size and description
20-30 µm - glass sensor
Oxygen Sensor
OX-50
Size and description
40-60 µm - glass sensor
Oxygen Sensor
OX-100
Size and description
90-110 µm - glass sensor
Options
100-400 µm
Extra price for option selection
20%
Oxygen Sensor
OX-100 Ultrafast
Size and description
90-110 µm - glass sensor
Options
Faster than 0.4 s
Extra price for option selection
15%
Oxygen Sensor
OX-200
Size and description
175-225 µm - glass sensor
Oxygen Sensor
OX-500
Size and description
400-600 µm - glass sensor
Options
600-800 µm
Extra price for option selection
20%
Oxygen Sensor
OX-Eddy
Size and description
150-200 µm - for Eddy Correlation System
Options
OX-Eddy (40-60 or 90-110 µm)
Extra price for option selection
20%
Oxygen Sensor
OX-MR
Size and description
400-600 µm - in guide
Oxygen Sensor
OX-N
Size and description
1.1 x 40 mm - needle sensor
Oxygen Sensor
OX-NP
Size and description
1.6 x 40 mm - needle sensor for piercing
Oxygen Sensor
OX-ST-1/4
Size and description
1/4'' steel tube
Oxygen Sensor
OX-SL-1/4
Size and description
FT-cell 1/4'' Swagelok Tee
Oxygen Sensor
OX-SL-1/8
Size and description
FT-cell 1/8'' Swagelok Tee
Oxygen Sensor
OX-PEEK-1/8
Size and description
FT-cell 1/8'' PEEK Tee
Oxygen Sensor
OX-PEEK-1/16
Size and description
FT-cell 1/16'' PEEK Tee
Oxygen Sensor
OX-FT-GLASS-6
Size and description
Glass FT-cell 6 mm outer diameter
Oxygen Sensor
OX-FT-GLASS-8
Size and description
Glass FT-cell 8 mm outer diameter

*In the standard design the O2 microsensor is optimized for stirring sensitivity and response time. However, it can be useful to focus on optimizing one of the parameters for special applications. Unisense offers to optimize the sensor concerning one or both of the above mentioned parameters. Optimization of these parameters makes the production more difficult, therefore the extra price.

Video Guides

O2 Quick Guide_450x260
Quick Guide O2 Microsensors

A walk-though of how oxygen microsensors are made, how they work, specifications, and customizations.

O2 Calkit contents
O2 Calibration Kit Video

Application Scientist Tage Dalsgaard shows you how to perform a 2-point calibration with a zero oxygen solution and water at atmospheric saturation

Related publications

An oxygen microsensor with a guard cathode
Revsbech, Niels Peter (1989), Limnology and Oceanography, vol. 34, 474-478
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Odor-Evoked Oxygen Consumption by Action Potential and Synaptic Transmission in the Olfactory Bulb
Lecoq, Je et al. (2009), Journal of Neuroscience, vol. 29, 1424-1433
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Long-term viability and function of transplanted islets macroencapsulated at high density are achieved by⁠…
Evron, Yoav et al. (2018), Scientific Reports, vol. 8, 6508
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Nitritation performance in membrane-aerated biofilm reactors differs from conventional biofilm systems
Lackner, Susanne et al. (2010), Water Research, vol. 44, 6073-6084
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Total nitrate uptake by an invasive benthic foraminifer in marine sediments
Choquel, Constance et al. (2020), Biogeosciences Discussions, vol. -, 1-33
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