O₂ Microsensor

High performance oxygen microsensor

With tip sizes down to 3-5 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...

If you are looking for inline monitoring of O₂ in reactors and flow-through systems, you can learn about the multiple mounting options here.

Manual

O₂ Microsensor Manual (PDF)

Technical Data

Ordering Information & Sizes

Configurations

Manuals & Videos

Quick Enquiry

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.

Manuals & Videos

Web lecture

Oxygen Microsensors

Description and time stamps:
00:00 Introduction
01:09 Tip design and detection principle
03:13 Specifications
09:35 Customizations
10:30 Troubleshooting

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 120-350 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

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 Detection limit - Low Range (OX-500-LR, OX-NP-LR)	Standard 0.050 µM
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 x 10^-4 - 5 x 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, OX-MR standard and FT-cell	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

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-500LR	Size and description 400-600 µm - glass sensor - low range	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-NPLR	Size and description 1.6 x 40 mm - needle sensor for piercing - low range
Oxygen Sensor OX-ST-1/4	Size and description 1/4'' OD steel tube
Oxygen Sensor OX-ST-12	Size and description 12 mm OD 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.