Robust, process conditions, autoclavable
- Oxygen in-line measurement in stainless steel fermenters
- In-line measurement of trace oxygen in brewing and beverage industries
- Small in size for environmental applications
Oxygen probes measure the partial pressure of both dissolved oxygen and gaseous oxygen. The oxygen sensor coating is integrated into high grade stainless steel fittings. The optical oxygen probes show an excellent long-term stability and stand rough process conditions. PreSens oxygen probes operate in industrial process control, trace oxygen measurement in the brewing and beverage industry and in various research applications.
- Autoclavable SIP (130 °C, 1.5 atm) & CIP (90 °C, 5 % NaOH)
- Probe is polarization free
- No membrane cleaning and replacement is necessary
- No electrolyte solutions to replenish
- Pressure resistant
- Long shelf-life
Oxygen Probe for In-line Measurement
The oxygen probe for in-line measurement (OIM) consists of a fitting made of stainless steel with an optical exchange cap (OEC). The OEC is screwed to the top of the metal fitting. The OIM is connected to the instrument via an optical fiber. The OIM has a standardized thread and length and is compatible with most bioreactors and port adapters. In addition, customized fittings for e. g. sight glasses are offered.
Oxygen Dipping Probe
The Oxygen Dipping Probe consists of a polymer optical fiber with a polished distal tip which is coated with a planar oxygen-sensitive foil.
The end of the polymer optical fiber is covered with a high-grade steel tube to protect both the sensor material and the optical fiber. The steel tube has an outer diameter of 4 mm and a length of 10 cm. The diameter of the fiber itself is 2 mm.
Due to the use of a polymer optical fiber, this probe is not compatible to temperatures higher than 70°C.
The Smart Measurement Method
The light from the blue-green LED excites the oxygen sensor to emit fluorescence. If the sensor spot encounters an oxygen molecule, the excess energy is transferred to the oxygen molecule in a non-radiative transfer, decreasing or quenching the fluorescence signal. The degree of quenching correlates to the partial pressure of oxygen in the matrix, which is in dynamic equilibrium with oxygen in the sample. The decay time measurement is internally referenced.
Examples for Applications
Process Control in Biotech & Pharma
The OIMs, the oxygen probes for in-line measurement, are designed for harsh conditions like high pressure or oil/water mixtures. These systems give high accuracy and are almost maintenance-free as they do not contain any membranes and electrolytes. The sensors are fully autoclavable and sterilizable (CIP & SIP).
In-line Oxygen Measurement in Brewing and Beverage Industry
Even low concentrations of oxygen influence shelf-life and the taste of certain beverages. Due to the extraordinary low detection limit of 1 ppb dissolved oxygen and outstanding accuracy of PreSens trace oxygen sensors, the quality of oxygen-sensitive products such as beer, wine and soft drinks is secured.
The optical sensors have – compared to standard electrodes – a very fast response time and they are very easy to maintain.
Long-term Measurements in Soil
PreSens offers dipping probes for oxygen measurement that does not consume oxygen. Due to their small dimensions they do not disturb the flow and mass-transport and consequently display the in-situ oxygen concentration. As minisensors from PreSens are long-term stable they can be implanted in soil for many years!
With this new method the process of soil aeration, which is very critical for plant productivity, can be investigated.
Dr. Heidi Heuberger, Technical University of Munich, Munich, Germany
Environmental Research – Investigation in Soil Filters
Due to the small outer dimension and mechanical robustness the oxygen dipping probe offers the possibility to measure the oxygen content in-situ in columns filled with filter sands during the flow of sewage (see picture on the left). The results show that a lack of oxygen stops the nitrification process.
Technical DataPlease click to enlarge.
Transmitter and Accessories
Fiber optic oxygen transmitter
4-channel fiber optic oxygen transmitter
10-channel fiber optic oxygen transmitter
Fiber optic oxygen transmitter with LCD display
OEC is designed for easy exchange.
The OAD-25 is used to connect all OIMs to 25 mm ports.