Portable Optical O2 Measurement in Liquids and Gases


OXYTRANS M is a portable optical oxygen sensor for measurement of O2 in e. g. deaerated water, wort, beer, beverages, liquid food, CO2 and protective gases.

The instrument is designed for applications requiring maximum sensitivity and highest accuracy. The measurement technology is based on the radiationless redistribution of excitation energy via molecular interaction. In the measuring head a small glass component with a thin layer of indicator molecules is installed, the optical window.

The indicator molecules are illuminated with blue-green light produced by an LED in the sensor. They absorb the incident light and are promoted to a higher energy state. After a certain time the molecules convert back to their ground state, during which red light is emitted. The red light is detected inside in the sensor. If O2 molecules are present the energy is transferred from the excited indicator molecules to the oxygen.

The detected signal decreases with increasing concentration of O2 molecules in the product. Other gases don’t absorb this energy, so they have no impact on the measurement result.

Typical Technical Data

  • Liquid Phase Measuring Ranges

    I) 1 ppb - 2 ppm
    II) 30 ppb - 35 ppm

  • Accuracies

    I) ±1 ppb
    II) ±30 ppb

  • Gas Phase Measuring Ranges

    I) 0 - 4.2% O2
    II) 0 - 50% O2

  • Accuracies

    I) ±0.002% O2
    II) ±0.03% O2

  • Response Time

    t90 ≤10s

  • Pressure of Operation

    max. 12 bar

  • Temperature of Operation

    23°F to 131°F (-5°C to +55°C) (Pt1000)
    option: 208°F (+98°C)

  • Material

    1.4404/AISI 316L, silicone (FDA), PTFE (FDA)

  • Datalogging

    manual/automatic with a logging time of 5 to 600 s; about 5,000 measurement values; PC software/USB-interface

  • Enclosure Rating


  • Power Supply

    battery, rechargeable


  • Optical technology; no electrolyte and membrane changes
  • Short response time and excellent long-term stability
  • Sturdy aluminum housing; low weight of just 1.65 kg