Description
The oxygen signal of the OROBOROS O2k is transmitted from the electrochemical polarographic oxygen sensor (OroboPOS) for each of the two chambers to DatLab. The primary signal is a current [mAmp] which is converted into a voltage [V], and calibrated in SI units for amount of substrance concentration [Β΅mol.dm-3 or Β΅M].
Reference: MiPNet19.18D O2k-Series G and DatLab 6: Calibration, MiPNet06.03 POS-calibration-SOP
|mitopedia method=Respirometry }}
MitoPedia O2k and high-resolution respirometry: O2k hardware, DatLab
MitoPedia O2k and high-resolution respirometry:
O2k-Open Support
Stability of the oxygen signal
The stability of the oxygen signal of the O2k is evaluated by the (negative) uncorrected slope over time. After smoothing, the slope of a stable sensor should be less than +- 1 pmol.s-1.ml-1 in a 2-ml chamber.
- Instability of the oxygen signal
- There is drift of the oxygen signal over short or long periods of time.
- The signal at air saturation is abnormally high for a given gain setting.
- The zero current is high (>2.5%) and may show drift.
- Follow the standard instructions for oxygen sensor service.
Oxygen signal does not respond
- The oxygen signal remains at or close to zero even at high oxygen levels.
- The signal at air saturation is abnormally low.
- Check the gain setting for the affected oxygen channel. Set to Gain 1.
- Apply technical service: O2k-Open Support
O2k-Open Support cases
- Anonymous user
Question:
Q1: The Oxygen Concentration couldn't go down while I tried zero oxygen calibration. No matter how much solution I added, the oxygen concentration still remain the same. I reassembled, but it still keeps the same. The data is attached. (2019-04-26)
Q2: The chamber B's oxygen slope is not stable. This is a new problem I have never seen. Please see the attachment.(2019-04-26)
Q3. The maximum Oxygen concentration of another Oroboros machine is only about 140. I don't how to increase the starting point of oxygen concentration. (2019-04-25-01)
Answer:
A1: I suspect that the dithionite solution was not correctly prepared or not fresh. Dithionite loses activity quite fast, so you need to make it freshly. Please check this site: http://bioblast.at/index.php/Dithionite
A2: While there is a difference between chambers A and B, the stability of the signal is still within the acceptable range of noise given by the specifications of the instrument, see: Oxygen_sensor_test.
A3: You may simply need to calibrate, please see here: http://wiki.oroboros.at/index.php/O2_calibration_-_DatLab