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MiPNet06.03 POS-calibration-SOP

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MiPNet06.03 POS-calibration-SOP

Publications in the MiPMap
O2k-Protocols
O2k Quality Control 1: Polarographic oxygen sensors and accuracy of calibration.

» Bioblast pdf

Oroboros (2016-02-09) Mitochondr Physiol Network

Abstract: Gnaiger E (2016) O2k Quality Control 1: Polarographic oxygen sensors and accuracy of calibration. Mitochondr Physiol Network 06.03(15):1-8. » Versions

O2k-Protocols SOP: High-resolution respirometry (HRR; Oroboros O2k) critically depends on maintenance POS-service and accurate calibration of the polarographic oxygen sensors (OroboPOS, POS). Standard operating procedures (O2k-SOP) are described as part of the MitoFit Quality Control System. (1) Clean and ready-to-use O2k-Chambers are a basic requirement. (2) Quality control for evaluation of proper POS function (SOP: O2 sensor test including the stirrer test). (3) Accurate POS calibration (air calibration and zero calibration). This is part 1 of O2k Quality Control.

» O2k-Protocols SOP: O2k Quality Control 2 »MiPNet14.06 Instrumental O2 background
» O2k-Manual: MiPNet19.18D_O2k-calibration
» Product: OroboPOS, Oroboros O2k, O2k-Catalogue
» Template: O2-calibration.xlsx


O2k-Network Lab: AT_Innsbruck_Oroboros


Labels: MiParea: Instruments;methods 





HRR: Oxygraph-2k, O2k-Protocol 

O2k-SOP 


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Template NextGen-O2k.jpg


MitoPedia O2k and high-resolution respirometry: O2k-Open Support 




Standard operating procedure

The O2 sensor test does not only serve to evaluate the function of the OroboPOS, but many other components of the O2k have to function according to specifications for a high-resolution oxygen signal to be obtained:
  1. USB-Cable 2.0\Type A-B not properly connected to the O2k and PC or Laptop.
  2. O2k-Chamber not properly positioned, such that O2 sensors are not connected to the medium.
  3. OroboPOS-Membranes defective or not properly applied.
  4. OroboPOS-Connector contaminated gold contacts; plugs not properly connected to the sockets of the O2k-Main Unit.
  5. OroboPOS contacts not cleaned. In rare cases, Pen-Contact Oil might be used.
  6. OroboPOS-Electrolyte Powder contaminated, inappropriate water used for dissolving the powder.
  7. O2-Zero Powder not properly handled; confused with OroboPOS-Polishing Powder.
  8. OroboPOS not properly serviced; not properly mounted to the OroboPOS-Connector; or defective POS head.
  9. Room temperature not sufficiently stable.
  10. Stirrer-Bar\white PVDF\15x6 mm not added to the chamber, or stuck and not rotating.
  11. O2k-Barometric Pressure Transducer not properly calibrated.
  12. O2k-Peltier Temperature Control defective electronics.
  13. O2k-Electromagnetic Stirrer Twin-Control defective electronics.
  14. O2k-Main Basic not properly connected; other defective hardware.

Trouble shooting

If the signal remains off scale (9.99 V) or very low (< 1 V) at air saturation (25 to 37 °C; lower signals at lower temperatures): Many components may be responsible, and an electronic defect of the O2k-Main Unit must be carefully excluded.
  1. Check settings for Gain (use Gain 1) and Polarization voltage (use 800 mV). If these settings were incorrect, the off-scale problem may be solved simply by using the standard settings.
  2. Empty the chamber with the O2k running and connected to DatLab. Switch the stirrer off. Remove the OroboPOS-Connector with the attached OroboPOS. Leave the sensor attached to the POS connector, and the POS connector plugged into the O2k-Main Unit. Record the signal for some minutes. The raw signal should normalize to a value >1 V and <3 V (Gain 1). If so, the O2k-Chamber assembly was problematic (application problem), and re-assembly will solve the problem. » O2k-Videosupport: Insert O2k-Chamber.
  3. Remove the sensor head from the sensor connector, which remains plugged into the O2k-Main Unit. If the raw signal is not stable at 0 V, a defect of the OroboPOS-Connector is indicated.
  4. Remove the plug of the OroboPOS-Connector from the O2k-Main Unit. A signal of 0.4 V, which remains stable when changing the gain, is a strong indication of an electronic problem in the O2k-Main Unit.
    1. For O2k-Series D and higher: The signal should be 0 V, otherwise an electronic problem of the O2k-Main Unit is indicated.
    2. For O2k-Series A to C: The signal should be off-scale (+/- 9.99 V), otherwise an electronic problem of the O2k-Main Unit is indicated.
If specifications given in the POS-SOP are not obtained: switch components for locating the problem.
  1. Switch the OroboPOS between O2k-Chambers A and B. This is a good opportunity to clean the gold contacts and apply Contact oil to the gold pin and thread connecting the POS connectors and sensors. It is not necessary to remove the seal tip and the mounted membrane from the OroboPOS. When disconnecting a sensor from the POS connector, prevent damage by electrostatic discharge by following the guidelines: MiPNet14.01 ESD-damage.
  2. Repeat the O2 sensor test. If the problem moved together with the sensor from one side to the other, the problem is located in the OroboPOS sensor.
  3. If the problem remained on the same side, switch the POS connector together with the attached sensors between right and left side (A and B).
  4. Repeat the O2 sensor test. If the problem moved together with the POS connector, it is located at the OroboPOS-Connector.

Oxygen solubility factor

cO2* is the oxygen concentration at thermodynamic equilibrium with air under standard conditions of 100 kPa barometric pressure. FM has been determined for MiR05 at 30 °C and 37 °C, and is assumed to be identical at 25 °C.

Instrumental O2 DLP

Instrumental DL-Protocols (DLP) are used for calibrations and instrumental quality control, typically without experimental sample in the incubation medium.

DL-Protocol Description DLP File
O2 calibration air OroboPos sensor test and calibration at air saturation O2 calibration air.DLP

A full list of DL-Protocols (Instrumental O2 DL-Protocols and SUIT O2 DL-Protocols) is displayed in DL-Protocols.

References

This article is cited in
  • Rodriguez JV, Pizarro MD, Scandizzi AL, Guibert EE, Almada LL, Mamprin ME (2008) Construction and performance of a minibioreactor suitable as experimental bioartificial liver. Artif Organs 32:323-8. »PubMed 18370948


O2k-QCS Next step - O2k Quality Control 2: MiPNet14.06 Instrumental O2 background