Southland Sensing manufactures a complete range of electrochemical oxygen sensors for ultra-trace, trace, percent, and oxygen-purity measurement. Our industrial oxygen sensors are manufactured in the USA at our Southern California facility.
Selecting the correct oxygen sensor involves more than simply choosing a measurement range. Sensor chemistry, expected oxygen concentration, exposure to ambient air, required response time, sensor life, and the composition of the process gas can all influence sensor selection.
This guide focuses on oxygen sensors used throughout Southland Sensing’s industrial oxygen analyzer platforms and provides a starting point for selecting the appropriate sensor based on measurement range, sensor chemistry, and application requirements.
In addition to sensors designed for Southland Sensing analyzers, we offer a wide range of direct-fit, drop-in replacement oxygen sensors for analyzers from other manufacturers, as well as custom sensor solutions for OEM applications.
Looking to replace a competitive oxygen sensor? View our دليل الاستبدال to find direct-fit replacement sensors for many popular oxygen analyzer brands.
Southland Sensing also works directly with OEMs to develop oxygen sensors for unique applications. Sensor output, measurement range, response time, expected life, electrolyte chemistry, mechanical configuration, electrical connection, and other performance characteristics can be customized to meet specific analyzer requirements.
| الفئة | Sensor | Recommended O₂ Range | Chemistry | Selection Guidance |
|---|---|---|---|---|
| Trace | TO2-1x | 1–10,000 ppm recommended (infrequent upsets up to 20.9%) | KOH | General-purpose trace sensor; the standard starting point for most trace O₂ applications where significant acid gas is not present. |
| Trace | TO2-2-2x | 1–10,000 ppm recommended (infrequent upsets up to 20.9%) | Acetic Acid | Trace sensor for CO₂ / acid-gas service; select when acid-gas compatibility is required. |
| Trace | تو2-238 | 1–10,000 ppm recommended (infrequent upsets up to 20.9%) | Acetic Acid w/ H₂S Scrubber Media | Specialized sensor for low-level O₂ measurement in CO₂ / natural gas streams containing < 500 ppm H₂S. |
| Ultra-Trace | تو2-133 | 0.045–1,000 ppm recommended (infrequent upsets up to 20.9%) | KOH | High-output trace sensor for very low ppm and sub-ppm measurement where greater low-level sensitivity is required. |
| Ultra-Trace | تو2-233 | 0.045–1,000 ppm recommended (infrequent upsets up to 20.9%) | Acetic Acid | High-output sensor for very low ppm / sub-ppm O₂ measurement in CO₂ and other acid-gas streams. |
| Hybrid Trace / Percent | TO2-19 | 45 ppm–25% O₂ | KOH | Hybrid sensor for applications spanning low ppm through percent O₂. Prolonged exposure to ambient air does not affect sensor life, making it well suited to applications routinely exposed to air. |
| النسبة المئوية | PO2-160 | 0.1% – 100% O₂ | KOH | General percent O₂ sensor when longer sensor life is preferred over faster response. |
| النسبة المئوية | PO2-24 | 0.1% – 100% O₂ | Acetic Acid | Percent O₂ sensor for CO₂ / acid-gas applications; use instead of a standard KOH percent sensor when CO₂ is present. |
| النقاء | ب2-1120 | 20.9% –100% O₂ | KOH | Designed specifically for elevated oxygen and oxygen-purity measurement, particularly applications operating continuously above ambient O₂. |
If you need help selecting a sensor, we have engineers available to go over your application and make a recommendation on the best fit.
One of the most important considerations when selecting an electrochemical oxygen sensor is the internal chemistry used inside the sensor.
Southland Sensing industrial oxygen sensors primarily use either potassium hydroxide (KOH) or acetic acid electrolyte chemistry.
KOH-based oxygen sensors are the standard choice for most industrial oxygen measurements.
They are commonly used for oxygen measurement in nitrogen, argon, helium, hydrogen, air, oxygen, hydrocarbons, and many other non-acidic process gases.
KOH sensors can also be an excellent choice for spot-checking oxygen in CO₂-containing gas streams, where exposure to CO₂ is intermittent and the sensor is returned to a non-CO₂ environment after testing.
For applications without significant concentrations of carbon dioxide or other acid gases, a KOH sensor is generally the preferred starting point.
Carbon dioxide and other acid gases can react with alkaline electrolytes such as KOH. For short-duration or intermittent measurements, such as spot-checking oxygen in CO₂, a KOH-based sensor can often be used successfully. However, prolonged or continuous exposure to CO₂ can affect sensor performance and reduce useful sensor life.
For applications requiring continuous oxygen measurement in CO₂ or other acid-gas-containing process streams, Southland Sensing offers sensors utilizing an acetic-acid-based electrolyte specifically suited for these environments.
These sensors are commonly selected for continuous oxygen measurement in CO₂, natural gas, biogas, fermentation, food and beverage processing, and other applications where prolonged exposure to acid gases is expected.
Applications containing hydrogen sulfide require additional consideration.
The Southland Sensing TO2-238 combines acetic-acid electrolyte chemistry with H2S scrubber media and is designed for trace oxygen measurement in CO2, natural gas, and similar process streams containing up to 500 ppm H2S.
For applications containing higher H2S concentrations or unusual gas compositions, please contact Southland Sensing to confirm sensor compatibility.
Not every trace oxygen application requires an ultra-trace sensor.
For most industrial applications measuring oxygen from approximately 1 ppm through 10,000 ppm, the TO2-1x family provides an excellent starting point.
Applications requiring reliable measurements below approximately 1 ppm should consider one of our higher-output ultra-trace sensors, such as the TO2-133 or TO2-233.
Trace oxygen sensors are designed primarily for operation at low oxygen concentrations.
Infrequent exposure to ambient air during calibration, maintenance, startup, or process upset is generally acceptable; however, prolonged operation at percent-level oxygen concentrations can reduce the expected life, slow the response time, and in some cases cause a loss of low-end sensitivity of a conventional trace oxygen sensor. For applications that are routinely shut down, consider a bypass isolation system to isolate the sensor in a low ppm oxygen gas. Ideally, during a shutdown or process pause, the sensor should remain isolated in a low-oxygen gas. Maintaining the sensor below approximately 1,000 ppm O₂ helps preserve expected sensor life, low-end sensitivity, and response performance.
For applications that routinely transition between trace oxygen and percent oxygen, or where prolonged ambient-air exposure is expected, the TO2-19 Hybrid Oxygen Sensor may be a better choice, assuming the low-end sensitivity is acceptable to the application.
The TO2-19 is designed for measurement from approximately 45 ppm through 25% oxygen and can tolerate prolonged exposure to ambient air without the same effect on sensor life as a conventional trace oxygen sensor.
Applications continuously operating above ambient oxygen concentrations have different requirements than conventional percent oxygen measurement.
The PO2-1120 is specifically designed for elevated oxygen and oxygen-purity applications, including oxygen generation and other processes operating continuously above ambient oxygen concentration.
For many oxygen-purity applications, the PO2-1120 provides a practical and cost-effective alternative to paramagnetic oxygen measurement, offering lower initial cost and reduced instrument complexity while offering a long life electrochemical sensor.
Southland Sensing designs and manufactures industrial electrochemical oxygen sensors at our Southern California facility. Sensor assembly, electrolyte preparation, testing, and quality control are performed in-house, allowing us to support standard replacement sensors as well as custom OEM sensor designs.
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