Retractable Needle-Type Oxygen Sensors
- Optical oxygen sensors
- Microsensors & Minisensors
- Original REDFLASH technology
- Works in gas (%O2) and in liquids (DO)
- No oxygen consumption
- Response times down to <0.3 s
- Sensor tip retractable in needle
- >3 years shelf time
- Stainless steel
- Optional underwater / deep sea versions
- Optional trace oxygen versions

These fiber-optic oxygen sensors offer unprecedented fast response times (down to <<1s) combined with high spatial resolution (down to ~50µm tip diameter). They are based on optical detection principles (REDFLASH technology). They assure very precise measurements, as they do not consume any oxygen and show no stirring sensitivity.
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Compatible oxygen meters
FireStingO2
(FSO2-x)
FireStingGO2
(FSGO2)
FireStingO2-Mini
(FSO2-MINI-ST)
FireStingO2-SubPort
(FSO2-SUBPORT) for sensors with underwater connectors (option
-SUB)
Normal Range Versions
| Item No. | Description (Needle / Tip Diameter) |
Response Time (s)** |
Pricing in EU* |
|---|---|---|---|
| OXR50 | Retractable Oxygen Microsensor (0.5mm / ca. 40-60µm) |
<2 s (liquid) <1 s (gas) |
230 € |
| OXR50-HS | Retractable Oxygen Microsensor (0.5mm / ca. 40-60µm), high speed |
<0.8s (liquid) <0.8s (gas) |
260 € |
| OXR50-UHS | Retractable Oxygen Microsensor (0.5mm / ca. 40-60µm), ultra high speed |
<0.3s (liquid) <0.3s (gas) |
290 € |
| OXR230 | Retractable Oxygen Minisensor (0.5mm / 230 µm) |
<2 s (liquid) <1 s (gas) |
290 € |
| OXR430 | Retractable Oxygen Minisensor (1.1mm / 430 µm) |
<2 s (liquid) <1 s (gas) |
290 € |
| OXR430-HS | Retractable Oxygen Minisensor (1.1mm / 430 µm), high speed |
<0.8 s (liquid) <0.8 s (gas) |
320 € |
| OXR430-UHS | Retractable Oxygen Minisensor (1.1mm / 430 µm), ultra high speed |
<0.3 s (liquid) <0.3 s (gas) |
350 € |
| OXR50-OI | Retractable Oxygen Microsensor (0.5mm / ca.40-60µm), optical isolation |
<3 s (liquid) <2 s (gas) |
290 € |
| OXR230-OI | Retractable Oxygen Minisensor (0.5mm / 230 µm), optical isolation |
<10 s (liquid) <4 s (gas) |
350 € |
| OXR430-OI | Retractable Oxygen Minisensor (1.1mm / 430 µm), optical isolation |
<10 s (liquid) <6 s (gas) |
350 € |
Trace Range Versions
| Item No. | Description (Needle / Tip Diameter) |
Response Time (s)** |
Pricing in EU* |
|---|---|---|---|
| TROXR430 | Retractable Trace Oxygen Minisensor (1.1mm / 430 µm) |
<15 s (liquid) <2 s (gas) |
290 € |
* Only EU-Prices shown. Contact us for pricing outside EU. Not for resale.
** Typical response times for 90% signal change
(T90).
For liquids: measured for the transition from
air into a stirred solution of 1% Na2SO3.
Options
| Item No. Extension | Description | Extra Charge |
|---|---|---|
| -CL4 | Cable length of ca. 4m (instead of standard 2m cable length) | add 30 € |
| -OI | Black optical isolation on the very sensor tip. Recommended for applications with intense background illumination (e.g. direct sun light) or for media with strong luminescent properties (e.g. very dense algae cultures). Refer to the tables above for available sensor versions. | see above |
| -HS | High speed. Selected sensors with fast response times. Refer to the tables above for available sensor versions. | see above |
| -UHS | Ultra high speed. Selected sensors with very fast response times. Refer to the tables above for available sensor versions. | see above |
| -SUB | Underwater connector (instead of standard ST-connector) needed for applications with the underwater OEM-solution FireStingO2-SubPort. Contact us for available sensor versions. | no extra charge |
| -CLx | Custom cable length of x meter (max. 20m) | on request |
| -Nx/y | Custom needle types (x mm in diameter, y mm in length) surrounding the sensor tip. Contact us for possible combinations. | on request |
Example: Item no. OXR430-HS-CL4-SUB designates a high
speed minisensor with 4m cable and with underwater connector.
Tip Geometries
True to scale drawings with syringe needle (grey), optical
fiber (pink), and oxygen sensitive REDFLASH dye (green)


Specifications
Given for 2-point calibrated oxygen sensors at 1013mbar absolute pressure.
| Normal range versions | hPa | %O2 | %air sat. | mg/L |
|---|---|---|---|---|
| Optimum measuring range | 0-500 | 0-50 | 0-250 | 0-23 |
| Maximum measuring range (not specified) | 0-1000 | 0-100 | 0-500 | 0-45 |
| Detection limit | 0.2 | 0.02 | 0.1 | 0.01 |
| Resolution at 1% O2 | 0.1 | 0.01 | 0.05 | 0.005 |
| Resolution at 20% O2 | 0.5 | 0.05 | 0.25 | 0.025 |
| Accuracy at 1% O2 | ±0.2 | ±0.02 | ±0.1 | ±0.01 |
| Accuracy at 20% O2 | ±2 | ±0.2 | ±1 | ±0.1 |
| Trace range versions | hPa | %O2 | %air sat. | mg/L |
|---|---|---|---|---|
| Optimum measuring range | 0-100 | 0-10 | 0-50 | 0-5 |
| Maximum measuring range (not specified) | 0-210 | 0-21 | 0-100 | 0-9 |
| Detection limit | 0.05 | 0.005 | 0.02 | 0.002 |
| Resolution at 0.2% O2 | 0.02 | 0.002 | 0.01 | 0.001 |
| Accuracy at 0.2% O2 | typ. 2% of | reading, but | not better | than 0.01%O2 |
| All versions | |
|---|---|
| Temperature range | 0 to 50°C (specified), -20 to 70°C (not specified) |
| Minimum lifetime | 1,000,000 data points |
| Application areas | Laboratory, industry, research. Not for medical or any other safety-critical applications. Not for application in humans or in food intended for human consumption. |
| Compatibility | Gas-phase, aqueous solutions, ethanol, methanol, isopropanol (note: the optional optical isolation (-OI) is not compatible to ethanol, methanol, isopropanol) |
| Cross sensitivity | Other organic solvents, chlorine |
| No cross sensitivity | pH 1-14, CH4, CO2, H2S, any ionic species |
| Sterilization | Ethylene oxide (EtO), 70% ethanol, 70% isopropanol |
| Cleaning | 3 % H2O2, ethanol, soap solution |
| Storage time | >3 years in darkness at room temperature |
| Calibration | Single point, two point calibration |
| Dimensions | Total length ca. 170 mm (from needle tip to cable), shaft diameter 8 mm |
| Needle length | 40 mm |
| Tip positions | Sensor tip adjustable at -6, 0, 6, 12 mm relative to needle tip |
| Connector | ST-plug (optional: underwater connector) |
| Cable length | 2m or 4m (standard), optional up to 20m |