Oxygen Sensor Details
Our oxygen sensor probes are both robust and simple to maintain. They are durable and long-lasting, though certain considerations are recommended to maintain quality performance. Probe lifetime is typically one year before reconditioning may be necessary. Read more about care & use below.
Basic cleaning of the probe is typically not required. New customers often see the red/orange sensor coating at the end of the probe, believe that it is some type of unwanted residue, and make an effort to remove this material. The red/orange coating is actually the oxygen sensitive chemistry that the NeoFox is interrogating.
Physical abrasion can cause the sensor chemistry to be compromised, or cause calibrations to shift. If your application involves direct contact with solids such as sand or dirt, a silicone overcoat is offered as a protection layer.
Sensors can be stored in dry or wet conditions, but should be stored in dark environments. When not using the sensor, the NeoFox should be turned off (unplugged) or the probe should be disconnected. The blue excitation LED in the NeoFox, and to a lesser extent ambient light, cause the sensor to slowly shift its calibration over long periods of time.
Handling of probes
Probes such as the OR125 and T1000 are very mechanically robust and can handle a good bit of mechanical stress without damaging the fiber. As the probes get smaller, however, it becomes easier to potentially damage the fiber from shock or bending past the minimum bend radius. The most fragile probe is the AL300, which does not have any outer ferrule for mechanical support.
Handling of patches
The patches can be installed into a vessel with an optically transmissive area, and then interrogated from the outside using the RE-BIFBORO-2 probe. The patches have a white backing liner that peels away exposing an adhesive layer, which allows for solid mechanical hold to glass or plastic. The adhesive is a high-performance silicone-based adhesive that has shown flawless mechanical rigidity and optical clarity for up to one month in seawater, DI water, pH 1 buffer, and pH 11 buffer. A razorblade is useful in separating the white backing from the sensor patch.
Point of measurement
When using the probes or patches, ensure that the probe tip or area of the patch being read is in the space which you want to know oxygen content. Whatever partial pressure of oxygen and temperature exist at the sensor chemistry will determine the reading the sensor provides.
Calibration is necessary to ensure that your probe reads oxygen levels accurately over the oxygen and temperature range at which you are working. You can calibrate your own probe, or have us calibrate prior to shipment.
We offer full calibration services for all of our probes and patches. The user can specify exactly which temperature ranges and oxygen concentrations they want the sensor calibrated for, so that the accuracy you achieve is fine-tuned for your specific application. We cycle the sensor through a range of temperatures and oxygen levels inside tightly controlled manifolds, and then provide a calibration file to be loaded onto your NeoFox electronics.
- Available temperature calibration range: -5 to 60°C (up to 80°C can be requested for custom runs)
- Available oxygen partial pressure calibration range: 0 – 1 atm
Optical oxygen sensors are affected by temperature. It affects both fluorescence intensity and excited state lifetime, resulting in a change in the calibration slope. To avoid false partial pressure readings, the sample must be held at constant temperature (±1°C), or corrected for temperature. Fortunately temperature compensation is easy with a properly calibrated probe and thermistor.
Ocean Optics oxygen sensors produce a fluorescence lifetime, or tau value, as a function of partial pressure of oxygen and temperature. To account for these temperature effects, we calibrate our sensors across a range of temperatures. By generating oxygen response curves at various temperature levels, a set of polynomial relationships are determined to provide precise oxygen readings despite changes in environmental temperature.
When ordering your custom calibration, please specify your expected operating temperature range. Temperature compensation can be achieved using our discrete thermistor or a probe with an integrated thermistor.
Are you working in the medical, healthcare, or food industries? Our FOSPOR coating formulation has been granted the USP Class VI certification, ensuring its safety and stability in these environments.
Our overcoated FOSPOR chemistry has achieved USP Class VI Certification for use in implantable devices, drug storage containers, and several other medical and pharmaceutical applications. These tests subject the material to long-term, heightened-temperature exposure to sesame oil, aqueous saline, alcohol in saline, and polyethylene glycol, and the subsequent solutions are injected in mice and rabbits for toxicity study.
Our FOSPOR material showed no biological effect on the test animals, and has been certified by the North American Science Associates Inc (NAMSA). FOSPOR is our most stable and reproducible oxygen sensor chemistry, and can provide hundreds of hours of stable readings with exceptional resolution.
Do you wonder if your environment is compatible with our oxygen sensors? View our chemistry compatibility table. If you work in an environment that’s not listed, please contact us.
|Short-term, ambient exposure does not cause a significant change to sensor accuracy|
|Short-term, ambient exposure causes a slight shift (<2%) to sensor accuracy|
|Short-term, ambient exposure compromises sensor accuracy|
|Environment||Oxygen Sensor Chemistry|
|3M Novec HFE-7100|
|Autoclave Cycle #2|
|JP-8 Jet Fuel|
|pH 1 Buffer|
|pH 13 Buffer|
|Water (pH 7.0)|
|Oxygen Sensor Chemistry|
|Operating Temperature||-200 – 60°C||-200 – 140°C||-200 – 100°C|
|Operating Pressure||0.15 – 10atm||0.15 – 2atm||0.15 – 5atm|
|Oxygen Partial Pressure||0 – 5atm||0 – 0.5atm||0 – 2atm|
|Matrix Composition||Polystyrene||Fluorinated Siloxane||Alkylated Siloxane|
|Response Time||2 – 5 seconds||0.1 – 1 seconds||1 – 3 seconds|
Curious how optical oxygen sensors compare to electrodes? See the electrode comparison.
|Ocean Optics Oxygen Sensor Systems||Commercial Electrodes|
|Measures both oxygen gas and dissolved oxygen in gases and liquids.||Most electrodes are designed for use in gas or liquids, but not both media.|
|Immune to environmental changes in pH, salinity and ionic strength.||Polarographic electrodes can be affected by changes in pH, salinity and ionic strength of the environment.|
|Immune to interference from moisture, carbon dioxide, methane and several other common substances.||Electrochemical electrodes are subject to interference from a number of substances and sampling conditions.|
|Fast response time — <1 second for dissolved oxygen and oxygen gas.||Electrodes can have a response time of 1-1.5 minutes, depending on temperature.|
|Long life — more than 1 year.||Electrodes have a typical lifetime of just 3 months.|
|Does not consume oxygen, allowing for continuous contact with the sample.||Electrodes can consume oxygen of ~0.1 micrograms/hour.|
|Frequent calibration is unnecessary.||Calibration may be necessary on an hourly basis.|
|Probe temperature range is -80°C to +80°C (up to 110°C for brief periods only)||Temperature range for some electrodes is 0°C to 45°C.|