Dissolved Oxygen

Three types of Dissolved Oxygen sensors are available for the XR and XRX series loggers

Oxyguard: Ocean Probe
Aanderaa: Oxygen Optode
JFE Alec: Rinko III

Ocean Probe (Galvanic) (used on the DO-1050 and the TDO-2050)

This small-size version of the standard OxyGuard dissolved oxygen probe is a membrane-covered galvanic cell that generates its own voltage. The Ocean D.O. Probe is designed for long-term measurements in ponds, lakes and oceans at depths up to 2000 m. Due to an ingenious pressure compensation system the probe is insensitive to pressure changes, and, as with all OxyGuard dissolved oxygen probes, it has built-in temperature compensation. It is, unlike some other types of dissolved oxygen probe, NOT sensitive to hydrogen sulphide. The Ocean D.O. Probe delivers a millivolt output directly proportional to the oxygen pressure that it senses. The connected electronics can therefore be quite straightforward.

• The probe is designed to be accurate at temperatures between 0 and 40°C, but can withstand temperatures up to 60°C.
• Useful range and resolution: 0-600% saturation dissolved oxygen. Resolution corresponds to 1% saturation.
• Response time: With fast response membrane 90% of step change within 10 seconds at 20°C. Response time is temperature dependant.
• Temperature Compensation: Built into probe. Temperature range: Recommended 0-40°C. Can be used up to 60°C.
• Pressure range: 0-2000 dbar.

Oxygen Optode 4330F

The AADI Oxygen optode was the first and only to measure dissolved oxygen for years without drift - now it is one of the fastest! The Oxygen optode is designed to measure absolute oxygen concentration and % saturation. The optode can be used from streams to deep sea, from fish farms to waste water and from polar ice areas to hydrothermal vents.
The lifetime-based luminescence quenching principle offers the following benefits:

• Response time <8 sec (63%)
• High accuracy
• Not stirring sensitive (it consumes no oxygen)
• Lower fouling sensitivity
• Measures absolute oxygen concentrations without repeated calibrations
• Better long-term stability
• Hot water monitoring
• Less affected by pressure
• Not sensitive to H2S
• Not freezing sensitive

Rinko III

CTD Profiling and Fast DO

Galvanic electrode DO sensors have been used for several decades to measure oxygen levels in water. Various in-situ optical DO sensors have been developed and commercialized. Both types of sensors have longer response times than desired, some as much as 20~50 seconds. Moreover these sensors can be unstable in the field. Therefore demand was high for someone to develop a new-technology sensor with fast response time, high stability and good accuracy. JFE Alec collaborated with Nara Women’s University since March 2007 to develop the reactive chemical material with suitable characteristics for a DO sensor, based on the existing PSP (Pressure Sensitive Paint) technology. The sensor is named "*RINKO". Deep-ocean validation (depths of 2000m to 6000m) show excellent results, proving RINKO’s potential in oceanographic research. (*Rinko means phosphorescence in Japanese.)

• Range 0 to 200%
• Resolution 0.01~0.04%
• Accuracy ±2% at 25°C
• Drift ±5%/month
• Response ~1 sec for 63% at 25°C