Zero Drift Optical O2 Sensors, drift free fiber optic Oxygen Sensors
Zero Drift Sensors are the most stable, optical based oxygen sensors available anywhere. 
Call us!  727-230-1697  or email info@zerodriftsensors.com with your application challenge.

*** Zero Drift Sensors work with Neofox electronics and all fiber assemblies from Ocean Optics ***

SEOX Optical Oxygen Sensor Systems - Ready to go - for Sale or Rent


Dissolved Oxygen (DO)  SensorsProcess Oxygen Sensors | pO2 SensorsOptical O2 Sensors for Fuels
 Phase Fluorometer Electronics| Optical O2 Sensor Application Notes | ZeroDrift Sensors Story | Technical Documentation & Software Downloads |

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Optical O2 Sensors

How to choose the right Optical O2 sensor


Optical Oxygen Sensors are characterized by the chemistry, deposition process, and optical fiber probe design:
***  Chemistries include AP, MR and HCR which are specific fluorophores in polystyrene or sol gel matrices.
***  Deposition includes dip coating directly on an optical fiber, or spin coating flat substrates that are subsequently mounted to fibers as removable screw caps.
***  Probe styles include:
 F Style - single dip coated fibers in steel tubes or ferrules (1/16", 1/8", 1/4" OD)
 FT style - dip coated probes with an integrated thermistors (5/32", 1/4" OD) The thermistor wire length (TX) is available in 5', 10', 20' or 30' lengths.

F style and FT style optical O2 sensors require a bifurcated fiber bundle SEOX-BB-1000-X (x = 5', 10', 20' or 30') and a 21-02 splice bushing.

RCT style - Removable oxygen sensor cap sensors with embedded thermistors 1/4", 3/8" OD). Fibers and thermistor wire are integrated into the probe and come in a 5' length.

The length of the fibers and thermistor cables for any of the probes can be extended using SEOX-EXT-1000-X (X = 5', 10', 20', 30') extensions.

Patches - These spin coated substrates (acrylic and glass) can be mounted for remote interrogation of dissolve O2 (DO) or gaseous O2 (pO2) by pointing a fiber probe at the back side of the substrate. This enables non-invasive monitoring of O2 inside of sealed containers. The patches are read with a bifurcated reflection/emission probe SEOX-BB-125

More details on probe styles

F style fiber optic O2 sensors
SEOX O2 sensors F style dip coated.

SEOX Optical O2 sensor zero drift with thermistor

sensor cap fiber optic O2 oxygen sensor with thermistor

Optical oxygen Sensor Chemistries
Performance characteristics of the three optical pO2 sensor chemistries are compared in the table below.
Chemistries  AP  MR  HCR
 Response

             fast

 fast  fast
 Aqueous samples  excellent  excellent  no
 Gases  excellent  excellent  dry only
 Organic solvents  no  no  excellent
 Resistance to H20 vapor  excellent  excellent  no
 Calibration Stability  excellent  excellent  excellent
 Stability in temperature extremes  medium  good  good
 Mechanical Stability  good  excellent  excellent

Probe style refers to the size and construction of the optical fibers, mechanical construction, sensor material deposition and other features such as built in temperature sensors. Most probe styles can be made with any of the chemistries. Custom probe styles are also available


SEOX F series optical O2 probes are 1000um optical fibers in 7" stainless steel ferrules. They have an SMA on one end and the chemistry dip coated to the angled sensor face. These are the simplest probes, and are generally used in controlled temperature environments, or with the external thermistor. F style sensors can be made smaller diameter than the other styles. On request we can make them integrated into needles for puncturing media, or in 1/32" OD probes. Standard models are:
SEOX-F116-A O2 Fiber Probe, 1000um, 1/16" OD x 7" A coating
SEOX-F116-HCR O2 Fiber Probe, 1000um,  1/16" OD x 7" HCR coating for hydrocarbons
SEOX-F125-A O2 Fiber Probe, 1000um, 1/8" OD x 7"  A coating
SEOX-F125-HCR O2 Fiber Probe, 1000um,  1/8" OD x 7" HCR coating for hydrocarbons
SEOX-F125-S-A O2 Fiber Probe, 1000um, 1/8" OD x 2.5" A coating
SEOX-F125-S-HCR O2 Fiber Probe, 1000um,  1/8" OD x 2.5" long HCR for hydrocarbons
SEOX-F250-A O2 Fiber Probe, 1/4" OD x 7"  55bar pressure rated & A coating
SEOX-F250-HCR O2 Fiber Probe, 1/4" OD x 7" 55bar pressure rated & HCR coating

process oxygen sensor pO2 DO and O2



F116 probe







FT series optical O2 probes are 1000um optical fibers in 7" stainless steel ferrules with a thermistor integrated into the probe body. These probes are available in 5/32" and 1/4" sizes. They are easier to use because of the embedded thermistor. Standard models include:

SEOX-FT156-A-T10 O2 Fiber Probe, 5/32" OD, 7" long, SS, thermistor, SMA & AP, 10' thermistor lead
SEOX-FT156-A-T20 O2 Fiber Probe, 5/32" OD, 7" long, SS, thermistor, SMA & AP, 20' thermistor lead
SEOX-FT156-A-T30 O2 Fiber Probe, 5/32" OD, 7" long, SS, thermistor, SMA & AP, 30' thermistor lead
SEOX-FT156-A-T5 O2 Fiber Probe, 5/32" OD, 7" long, SS, thermistor, SMA & AP, 5' thermistor lead
SEOX-FT156-HCR-T10 O2 Fiber Probe, 5/32" OD, 7" long, SS, thermistor, SMA & HCR, 10' thermistor lead
SEOX-FT156-HCR-T20 O2 Fiber Probe, 5/32" OD, 7" long, SS, thermistor, SMA & HCR, 20' thermistor lead
SEOX-FT156-HCR-T30 O2 Fiber Probe, 5/32" OD, 7" long, SS, thermistor, SMA & HCR, 30' thermistor lead
SEOX-FT156-HCR-T5 O2 Fiber Probe, 5/32" OD, 7" long, SS, thermistor, SMA & HCR, 5' thermistor lead
SEOX-FT250-A-T10 O2 Fiber Probe, 1/4" OD, 7" long, SS, thermistor, SMA & AP, 10' thermistor lead
SEOX-FT250-A-T20 O2 Fiber Probe, 1/4" OD, 7" long, SS, thermistor, SMA & AP, 20' thermistor lead
SEOX-FT250-A-T30 O2 Fiber Probe, 1/4" OD, 7" long, SS, thermistor, SMA & AP, 30' thermistor lead
SEOX-FT250-A-T5 O2 Fiber Probe, 1/4" OD, 7" long, SS, thermistor, SMA & AP, 5' thermistor lead
SEOX-FT250-HCR-T10 O2 Fiber Probe, 1/4" OD, 7" long, SS, thermistor, SMA & HCR, 10' thermistor lead
SEOX-FT250-HCR-T20 O2 Fiber Probe, 1/4" OD, 7" long, SS, thermistor, SMA & HCR, 20' thermistor lead
SEOX-FT250-HCR-T30 O2 Fiber Probe, 1/4" OD, 7" long, SS, thermistor, SMA & HCR, 30' thermistor lead
SEOX-FT250-HCR-T5 O2 Fiber Probe, 1/4" OD, 7" long, SS, thermistor, SMA & HCR, 5' thermistor lead
SEOX-FT375-A-T10 O2 Fiber Probe, 3/8" OD, 7" long, SS, thermistor, SMA & AP, 10' thermistor lead
SEOX-FT375-A-T20 O2 Fiber Probe, 3/8" OD, 7" long, SS, thermistor, SMA & AP, 20' thermistor lead
SEOX-FT375-A-T30 O2 Fiber Probe, 3/8" OD, 7" long, SS, thermistor, SMA & AP, 30' thermistor lead
SEOX-FT375-A-T5 O2 Fiber Probe, 3/8" OD, 7" long, SS, thermistor, SMA & AP, 5' thermistor lead
SEOX-FT375-HCR-T10 O2 Fiber Probe, 3/8" OD, 7" long, SS, thermistor, SMA & HCR, 10' thermistor lead
SEOX-FT375-HCR-T20 O2 Fiber Probe, 3/8" OD, 7" long, SS, thermistor, SMA & HCR, 20' thermistor lead
SEOX-FT375-HCR-T30 O2 Fiber Probe, 3/8" OD, 7" long, SS, thermistor, SMA & HCR, 30' thermistor lead
SEOX-FT375-HCR-T5 O2 Fiber Probe, 3/8" OD, 7" long, SS, thermistor, SMA & HCR, 5' thermistor lead



RCT Series Optical O2 Probes have embedded thermistors

RCT series probes have a thermistor embedded in the probe body, to provide temperature compensation. Fibers are also integral parts of the probe. The standard length of the thermistor cable and fibers is 5'. Extensions can be added to elongate the probe cables. RCT probes have removable sensor caps. These are sensor discs permanently mounted in a threaded cap. These probes have the advantage that the user can change chemistries just by changing caps. They are available in these standard models:

SEOX-RCT250-A Screw cap O2 Sensor, 1/4" OD, 7" long, SS, thermistor,SMA, & AP chem
SEOX-RCT250-HCR Screw cap O2 Sensor, 1/4" OD, 7" long, SS, thermistor, SMA & HCR chemistry
SEOX-RCT250-MR Screw cap O2 Sensor, 1/4" OD, 7" long, SS, thermistor, SMA & MR chemistry
SEOX-RCT375-A Screw cap O2 Sensor, 3/8" OD, 7" long, SS, thermistor, SMA &  AP cap
SEOX-RCT375-HCR Screw Cap O2 Sensor, 3/8" OD, 7" long, SS, thermistor, SMA & HCR cap
SEOX-RCT375-MR Screw Cap O2 Sensor, 3/8" OD, 7" long, SS, thermistor, SMA & MR cap


zero drift optical oxygen sensor for process control

RCT375 probe with fibers and thermistor cable











Optical O2 Sensor Chemistry & probe Specifications

AP formulation

Polystyrene matrix

HCR formulation

Sol Gel matrix

MR formulation

Sol Gel matrix

Response Rate

T90 = 3 sec

T90 = 1 sec

T90 = 1 sec

Dynamic Range (gas)

0 – 760 mmHg

0 – 100% (at 1 atm)

0 – 760 mmHg

0 – 100% (at 1 atm)

0 – 760 mmHg

0 – 100% (at 1 atm)

Dynamic range (DO)

0 – 40 ppm in H2O

0 – 40 ppm in H2O

0 – 40 ppm in H2O

Resolution (gas)

0.04 mmHg

0.005% (at 1 atm)

0.4 mmHg

0.05% (at 1 atm)

0.4 mmHg

0.05% (at 1 atm)

Resolution (DO)

0.002 ppm in H2O

0.002 ppm in H2O

0.002 ppm in H2O

Accuracy

5% of reading

5% of reading

5% of reading

LDL (gas)

0.04 mmHg

0.005% (at 1 atm)

0.4 mmHg

0.05% (at 1 atm)

0.4 mmHg

0.05% (at 1 atm)

LDL (DO)

0.002 ppm in H2O

0.002 ppm in H2O

0.002 ppm in H2O

Drift rate

No measureable long term drift, continuous operation

0.0001 % /hr in gas

0.0001 % /hr in gas

Sensor Operating Temperature

-50 to 100C

-50 to 200C

-50 to 200C

Useful Lifetime

3 years

3 years

3 years

Compatibility

General purpose gases and aqueous solutions

Organic solvents

General purpose gases and aqueous liquids

Water Vapor Interference

no

yes

no

Formats

Dip coated fibers

Spin coated patches & probes

Dip coated fibers

Spin coated patches & probes

Dip coated fibers

Spin coated patches & probes

Review

Best general purpose probe, longer fluorescence decay yields more resolution, zero drift means stable calibrations

Used for organic solvents and gases with organic vapors.  This sensor does respond to water vapor as well as O2

General purpose but with faster response rate than AP chemistry. Does exhibit long term photo-bleaching drift and has less resolution.


 

Dissolved Oxygen DO Sensors

Any of the optical O2 sensor styles can be used for dissolved oxygen. AP chemistry is especially good for DO measurement in water based media. The reflective white overcoat improves the signal strength and protects the probe from dirt, debris and fouling found in natural waters. For field work our portable NEOFOX-SPORT is ideal.  HCR chemistry is used to make optical DO measurements in organic fluids.

 

Process and Laboratory Oxygen Sensors

Optical O2 Probe bodies are made of stainless steel tubes to encase the optical fibers. These probes can be inserted into compression style tube fittings for introduction into pipes are reactors, or they can be dipped into open containers of liquids. Pressure ratings for the SEOX F series O2 probes are 55 bar. Probes can be made with custom lengths, diameters and flanges.

 pO2 optical Sensors

The MR sensor chemistry is especially formulated for fast response and moisture resistance for measuring optical pO2 (partial pressure of oxygen) in gas streams. It can withstand high temperatures and has a response rate < 1sec.

 Fuel and Hydrocarbon pO2 sensors
SEOX HCR chemistry is designed to work in aggressive organic solvents -- acetone, toluene, Jet-A, kerosene. It is available on any of our style probes.  In patch format glass substrate is required.  While typical optical oxygen sensors can dissolve in organic solvents, HCR is a special sol-gel (room temperature glass polymer) that does not dissolve. In addition organic vapors that might interfere with the quenching mechanism are blocked.  Using HCR sensors may require calibration in your solvent. We can do this at the factory in most cases, or can help you establish a reliable calibration protocol.

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Zero Drift Oxygen sensor and neofox electronics

 

F250-HCR optical O2 probe shown with the NEOFOX Phase Fluorometer.  The Neofox is easily adaptable to process applications that require an analog or digital output.  Download the Neofox manual for more details.

Download NEOFOX Users Manual



Disposable Plastic optical O2 Sensors

   

These optical O2 probes are inexpensive, could almost be considered disposable! They are made with PMMA plastic fibers and standard SMA connectors. They are not as rugged as the stainless steel variety, but work just as well in terms of the signal strength. The probes are 6" long and come in a variety of diameters. They do not come with a factory calibration and are only available in the SEOX Zero drift AP chemistry.


SEOX Optical O2 Sensor Patches and Discs

Optical oxygen non-invasive sensor discs are clear acrylic coated with SEOX AP optical O2 sensing chemistry or glass with optical O2 sensing HCR coating on the front side. They can be glued in place and read by pointing a a bifurcated probe at the back side of the disc. If they are mounted on a clear container wall, you can read pO2 in the inside of the container from the outside, without disturbing the sample, hence "non-invasive O2 measurements." This is very useful for measuring respiration, monitoring O2 in sterile environments and bioreactors, and other sealed systems such as glove boxes, incubators or products packaged in modified air packaging (MAP). The drawing below shows an installation with a RCT probe installed in a compression fitting put through the container wall (lower), and an SEOX patch being read through the wall of the container with a bifurcated fiber probe.

Optical O2 non-invasive patches - Spectrecology






Fiber Assemblies Used with Sensors



SEOX-BB-1000 Bifurcated borosilicate fiber, SMA, for 1000um sensors 

SEOX-BB-125 Bifurcated bundle with 1/8" ferrule for reading sensor discs

 

Special - Custom Optical O2 Fiber Sensors

Spectrecology makes custom sensors designed for your specific application. These custom sensors may be simply longer or shorter, or have longer optical fibers. But we often make special tools for specific applications. here are a few examples:

Sensor for measuring pO2 in beach sand

- Optical O2 sensor in a keyed needle that could be inserted into hard packed sand along the shoreline. The optical O2 sensor was made in a 1mm diameter tube that fit into a large needle. The sensor was keyed and fixture to maintain its orientation in the needle.  The whole assembly was pushed into the sand, with the delicate sensor withdrawn a few mm to protect it from abrasion. Then the needle was drawn back to expose the tip.  The project involved measuring pO2 as a function of depth in the sediments.

- Optical O2 sensor for biofuel storage tanks.  Oxidation of biofuels is an issue, and measuring pO2 in storage tanks and ponds is important. We make a special optical O2 sensor using HCR chemistry, and long fibers on a pole for dipping into the tanks.

- Optical O2 sensor for measuring pO2 in the eye.  That's right! In your eye!  pO2 varies with depth from the cornea to the interior, and that gradient can be diagnostic of eye diseases and disorders. We made a small (200um) sensor in a tiny 22 gauge needle. The same technique we used in sediments was used here... insert the needle into the tough eye tissue, and pull the needle back to expose the sensing tip.