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Why use an online dissolved oxygen sensor?

In biological processes like fermentation and cell culture dissolved oxygen is critical to support proper cell growth. In industrial processes, oxygen is often limited in applications where corrosion is of concern. Online oxygen measurement enables real-time control of dissolved oxygen at a predefined set point or enables the detection of a leak in the process that is resulting in oxygen infiltration.

Optical Dissolved Oxygen Sensors

Optical Dissolved Oxygen Sensors

The VisiFamily of optical dissolved oxygen sensors are quickly replacing polarographic installations due to a more robust measurement and minimal maintenance.

Polarographic Dissolved Oxygen Sensors

The OxyFamily of traditional polarographic sensors has an industry-leading two hour polarization time and modular design to simplify maintenance.

Single-Use Dissolved Oxygen Sensors

The VisiFerm sensing element can now come pre-installed and gamma irradiated in your favorite single use bag or bioreactor.

Do you know all the potential sources of DO measurement error?

dissolved oxygen whitepaper

Much has been written about different strategies for proper DO control. However, little information has been publicly available regarding optimization of the actual measurement accuracy and reducing common sources of process-related error.

Get Hamilton's whitepaper on potential sources of optical dissolved oxygen measurement error and ways to mitigate the impact.

Get the White paper

Polarographic vs. Optical Dissolved Oxygen Probes

For over 60 years polarographic sensors have been used to measure dissolved oxygen through the electrochemical reduction of oxygen with a noble metal. More recently optical oxygen has gained prominence by eliminating polarization time, electrolyte, and complicated maintenance, by requiring only a single replacement part.


Optical Dissolved Oxygen Sensors

The VisiFamily of sensors have a blue LED in the sensor shaft and an oxygen sensitive dye (luminophore) fixed to a glass window in the replaceable sensor cap. The blue light excites the luminophore and then a photodetector in the sensor shaft senses the red light that is returned from the luminophore. A microprocessor in the sensor correlates the emitted blue light and the measured red light to partial pressure of oxygen. This measurement can then be output as a simulated nA signal, 4 - 20 mA, or digital protocol.

See all optical sensors

Polarographic "Clark Cell" Dissolved Oxygen Probes

Classical Clark cell sensors have a platinum cathode and a silver anode that are separated from the sample by a gas permeable membrane. As oxygen diffuses across the membrane it is reduced resulting in a small nA current. The more oxygen the stronger the current. This current is then detected by a separate transmitter which amplifies the signal for process control.

See the DO measurement guide

Specific Applications


Hamilton's knowledge base provides a range of explanatory articles, frequently asked questions, and document downloads.
  • Brochure - BioPharma

    Innovative solutions for process analytics in biotechnological and pharmaceutical industries.
  • Brochure - Optical Dissolved Oxygen

    Download the dissolved oxygen brochure to explore the many benefits of making the switch to optical oxygen measurement.
  • Brochure - VisiFerm mA Dissolved Oxygen Sensors

    Hamilton extensively investigated the effects of the bioprocess on measurement accuracy. Analysis of sensor aging, chemical attack, and physical damage yielded the necessary understanding for development of a next generation VisiFerm which reduces the need for frequent calibration.

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