dissolved or atmospheric oxygen microsensor


Dissolved O3 Probe

  • Measure oxygen at the microscale
  • Rapid response time of 200 milliseconds
  • Sensor diameter tips < 25 μm
  • Delivered to you calibrated and ready to measure
  • Robust and accurate oxygen measurements

The galvanic O2 micro-sensor has been developed for the in-situ determination of oxygen containing aqueous solution. Therefore the sensor is suitable for direct measurements in lakes, estuarines, rivers, oceans and sediments.

Compared with all the other commercially available oxygen sensors, this galvanic oxygen microsensor works with such a low analyte consumption, that streaming of the sensor membrane or stirring of the analyte is not necessary. Therefore an additional stirrer is not necessary for stationary measurements.

The second main difference to other dissolved oxygen sensors is the very fast response time of the galvanic oxygen micro-sensor with T90% down to 200 milliseconds compared with approximately 6 to 20 seconds in the case of the conventional sensors.

The third advantage of the new microsensor is founded in the microsensor technology. Galvanic oxygen microsensors are working with a high local resolution and allow profiling with μm-steps. Therefore also measurements in soft sediments or mud became practicable.


more details

The main operating principles of the oxygen microsensor are diffusion of oxygen through a porous membrane where the oxygen molecules undergo an electrochemical reaction to create an electrical signal. This type of sensor is also known as a galvanic or Clark-type microsensor.

The ES-O2-SW operates via a difference in partial pressure between the environment being measured and inside the sensor. Oxygen passes through the membrane via diffusion.

The membrane is only pervious to gases, so that liquids, ions and solids are not able to reach the inner electrolyte of the sensor. Inside the sensor contains a buffered solution and 3 electrodes. The electrode materials are selected carefully to realize a self polarization for requested electrochemical reduction of oxygen at the working electrode surface. Therefore essential shorter times for putting into operation after switching on are observed compared with the normally delivered amperometric sensors.

If the O2 passes now the membrane, the oxygen is transported by diffusion to the working electrode followed by the electrochemically reduction of the O2. This causes a current depending on the oxygen partial pressure/oxygen concentration of the analyte. The observed very small current within a range of some hundred picoamperes is converted into a voltage of 0...5 Volt (main working range: 0...1,500 mV) inside the integrated electronic device of the sensor. Besides, the current flow in the galvanic sensor leads to a rapid decrease of the analyte inside the sensor resulting in very fast response times. This is also observed, if a rapid change from high to very low concentration levels is necessary.

All electrochemically working oxygen sensors have to be combined with a temperature sensor.

When ordering a complete submersible probe system, the temperature measurement and the temperature correction of the sensor signal is already included. If measurements in a flow through system are required, special temperature sensors for the integration in flow through cells are offered.

When measuring in opened vessels or beakers in the laboratory, the customers have to realize the temperature measurement themselves. If a sensor with temperature compensation data is ordered, the temperature correction of the signal is very easy by means of a factor or for more accurate measurements by means of a mathematical formula.


whole system monitoring solutions

Edaphic Scientific is a one-stop shop for a whole system monitoring solution. We provide water quality monitoring systems for researchers and industry.

Our systems not only support dissolved gas sensors, but related sensors such as temperature, weather sensors, and many more.

At Edaphic Scientific we want to work with you from the start of your project through to its completion. We can provide:

  • Assistance with project and experimental design
  • Procurement of all monitoring equipment, including sensors, data loggers and data management software. Edaphic Scientific is a one-stop shop where we can source and find any necessary equipment for your project from our preferred suppliers or third party suppliers
  • Installation and training
  • Ongoing assistance with data interpretation and equipment maintenance
  • Data correction and analysis, including statistical analysis with the R-package
  • Report and publication preparation including tables, figures, graphs, and manuscript writing


advanced data collection and management solutions

Edaphic Scientific recognises the need for flexible and adaptable sensor and data logging solutions for experimental or environmental monitoring projects.

Data can be downloaded directly in the field from data loggers. A direct connection between the data loggers and your computer, via a USB cable, can be used for manual downloading of data.

Alternatively, data can be downloaded over the internet on your iPhone, iPad or desktop computer with the cloud-based, data management software solutions. Through this remote based downloading capabilities, you can download, view and manage your data, and system, anywhere in the world and at anytime.


feature specification
Measurement Principle amperometry, membrane covered sensor
Accuracy better than 2% of the measuring value
Measurement Range & Resolution range: 0...150% saturation (others on request) | resolution: ~ 0.1%
Response Time (T90) approx. 200 milliseconds
Sensor Lifetime application dependent; approx. 6...24 months
Environmental Tolerance Temperature: 0°C and 30°C
Cross Sensitivities Against Higher H2S concentrations for long times lead to rapidly decreasing life times and sometimes to false results or to a damage of the sensor
Polarisation Time 5 to 15 minutes upon initial measurement
Stirring Senstivity no streaming of the membrane necessary, no stirring of the analyte, very low analyte consumption
Power Supply 9 to 30 VDC
Signal Output 0 to 3 V
Sensor Dimensions tip diameter: ~25 um | total diameter: 24 mm | length: 235 mm
Housing Titanium
Cable Length & Connector 5m (standard; others on request) | SUBCONN BH-4-MP
Depth Rating 100 m | 10 bar

manuals & docs

related products