View source for OroboPOS

{{Product
|description=The '''OroboPOS''' is a polarographic oxygen sensor (POS), with an amperometric mode of operation. The OroboPOS meets the highest quality criteria in terms of linearity, stability and sensitivity of the signal. The Clark type polarographic oxygen sensor (POS) remains the gold standard for measuring dissolved oxygen in biomedical, environmental and industrial applications over a wide dynamic oxygen range.

It consitsts of a gold cathode, a silver/silverchloride anode and a KCl electrolyte reservoir separated from the sample by a 25 µm membrane (FEP). The main body of the OroboPOS is made of PEEK. With application of a polarization voltage (0.8 V), a current is obtained as an amperometric signal, which is converted to a voltage.
|product id=26000-01
|product type=O2k, OroboPOS
|info= [[MiPNet08.04]], [[Gnaiger_1983_POS]]
|product image=[[Image:OroboPOS sensor head.jpg|right|180px]]
}}
== Specifications ==


'''From nM to mM O2 - a million-fold dynamic range''': The dynamic range of oxygen measurement spans from air saturation (about 200 µM) to the normoxic intracellular range (10-30 µM) and severe hypoxia (<1 µM), but also to hyperoxia (oxygen saturation: c. 1 mM). In measurements of cell respiration in conjunction with the [[Titration-Injection microPump|Titration-Injection microPump TIP2k]], allow accurate steady-state measurement of oxgen levels and respiration with resolution of better than ±1 nM. 

== Shipment ==
* [[O2k-Core]]: [[2 OroboPOS]] are included and shipped in the [[O2k-Service Box]]. A spare (third) OroboPOS may be added to the items ordered with the O2k-System.

OroboPOS are protected in a transparent perspex vial screwed onto a blue POM base, with the [[OroboPOS-Membrane Ring]] arrested on the POS shaft between the POM base and the thicker part of the POS head which holds an [[O-ring\Viton\8x1 mm]].

== POS service and membrane mounting ==
>> [[MiPNet08.04 POS-Service|O2k-Manual for OroboPOS Service]] 

>> [[OroboPOS-Service Kit]]


== OroboPOS Technical Service Pages ==
{{#ask: mainlabel=Title|[[Category:All]] | [[Technical service::O2 sensor||O2 signal ]]| ?Technical service}}


== Trouble shooting ==

If a [[Stirrer test]] shows a slow response of the sensor some hints in [[Slow responding sensor]].

As the heart of the OROBOROS Oxygraph-2k the OroboPOS is of course the prime suspect when any kind of troubles are encountered. However, frequently problems can be traced either to inadequate software settings or to other hardware components (like the [[POS connector (technical service) |POS connector]]).
Therefore it is important to confirm the problem doing a [[Sensor test]] and to [[Locating a problem |localize the problem]].

=== Problems that require a full Sensor test and localization of the problem ===
*unstable O2 signal
*unstable O2 flux
*high O2 signal at air saturation
*high O2 signal at zero oxygen

===Special cases: no further localization necessary ===
* [[Slow responding sensor]], if this has been confirmed by a [[Stirrer test]]. Note: The stirrer test is part of the sensor test. It is therefore recommended to do a full [[Sensor test]] whenever problems are encountered.

===General Trouble Shooting Procedure for the OroPos ===

Confirm the problem by doing a [[Sensor test]] in the absence of biological material

====Option 1.A: No problem was visible in the [[Sensor test]]====
check the following DatLab settings
* [[Gain (O2 channel)]]
* [[POS calibration]]
* Scaling

If the problem is not visible when observing the [[Raw signal]] but is visible when observing the calibrated oxygen signal, then there is probable a problem with the [[POS calibration]].

====Option 1.B: The problem was visible in the [[Sensor test]]====
* proceed to [[ Locating a problem|Locate the Problem ]] and the continue as stated below

====Option 2.A: The problem could be localized on the [[POS]]====

'''Solutions 2.A'''
Follow the instructions for oxygen sensor service [http://www.oroboros.at/index.php?id=o2k-pos-service [MiPNet08.04]]. Use this opportunity to apply [[contact oil]] to the gold pin and thread connecting [[POS]] and [[sensor connector]]. After a sensor service or after applying anew membrane allow the oxygraph to run over night to achieve a stable signal before repeating the [[sensor test]].
If all service precautions fail to solve the problem, the [[POS]] has to be sent to us for further service (a recovery can not be guaranteed), or a new sensor is to be applied.

====Option 2.B: The problem was not localized on the [[POS]]====
'''Solutions 2.B'''
If the problem was localized on an other component follow the instructions for this component. If you could not locate the problem contact OROBOROS Instruments.


== References ==

* Gnaiger E, Forstner H, eds (1983) Polarographic Oxygen Sensors. Aquatic and Physiological Applications. Springer, Berlin, Heidelberg, New York: 370 pp.
* Gnaiger E (2001) Bioenergetics at low oxygen: dependence of respiration and phosphorylation on oxygen and adenosine diphosphate supply. Respir Physiol 128: 277-297.
* Gnaiger E (2008) Polarographic oxygen sensors, the oxygraph and high-resolution respirometry to assess mitochondrial function. In: Mitochondrial Dysfunction in Drug-Induced Toxicity (Dykens JA, Will Y, eds) John Wiley: 327-352.



{{Technical service}}


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