High signal at zero oxygen

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

Description

A high signal at zero oxygen may be observed during zero calibration (R0). First, check the quality of the dithionite solution. The following instructions show how to distinguish between a defective sensor head and an electrical leak current.

Reference: Zero calibration, OroboPOS-Connector

Leak current test

O2k-series J and XB

O2k-series D-I and XA

1. Unscrew the POS from the POS-Connector and unplug the POS-Connector from the O2k-main unit.

2. Switch on the O2k and start DatLab.

3. Record the signal for 10 min.

4. Connect the POS-Connector to the O2k-main unit without the POS. Set an event in DatLab called "POS-Connector".

5. Record the signal for 10 min.

6. Remove the membrane from the POS and wash the cathode and anode with distilled water.

7. Screw the POS to the POS-Connector. Set an event in DatLab called "POS".

8. Record the signal for 10 min.

9. Send us the file.

O2k-series A-C

Please start with the POS-Connector already connected to the main unit and proceed with step 5.

References

[1] Cleaning the electrical connections

[2] MiPNet19.18B POS-service

[3] MiPNet06.03 POS-calibration-SOP

[4] MiPNet14.06 Instrumental O2 background

Example: First, the OroboPOS-Connector and the POS were disassembled and disconnected from the main unit. Second, the OroboPOS-Connector was connected to the O2k-Main unit without the OroboPOS. Third, the OroboPOS was connected to the OroboPOS-Connector without membranes. After each step, the O₂ raw signal [V] was recorded for 10 min. The marks were set to the O₂ raw signal [V] to evaluate the zero current.

Figure 1. High zero current test. Upper panel: Zero current is in the range of ±0.00099 V. Lower panel: Zero current is higher than 0.00099 V when the OroboPOS-Connector is connected to the O2k-Main unit and when the OroboPOS is connected to the OroboPOS-Connector, indicating a potential electrical problem with both the OroboPOS-Connector and the OroboPOS.