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MiPNet06.05 Test Experiments on O2k-Specifications

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Publications in the MiPMap
OROBOROS
Gnaiger E (2001) Test experiments on specifications of the OROBOROS Oxygraph. Mitochondr Physiol Network 6.5. »Bioblast pdf«

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OROBOROS (2001) Mitochondr Physiol Network

Abstract: Summary: The OROBOROS Oxygraph with DatLab software is world-wide the only instrument on the market which allows routine measurements to be made with specifications summarized under the term “high-resolution respirometry”: The limit of detection of O2 flux is as low as 0.5 pmols-1cm-3. Signal noise at zero oxygen concentration is <0.05 μM O2. Oxygen backdiffusion at zero oxygen is <3 pmols-1cm-3, and oxygen consumption at air saturation and standard barometric pressure (100 kPa) was 2.7 +/- 0.9 SD in 114 test runs at 37 °C. These highly standardized instrumental background fluxes are a linear function of oxygen concentration, which is used for routine background correction of oxygen flux. Typical exponential time constants of the oxygen sensors are <4 s, used for dynamic corrections in kinetic studies. Results of an extensive experimental test program are presented as the basis of OROBOROS Oxygraph specifications, which distinguish high-resolution respirometry from any conventional oxygraph system.


O2k-Network Lab: AT Innsbruck OROBOROS


Labels: MiParea: Instruments;methods 





HRR: Oxygraph-2k 


The OROBOROS Oxygraph-2k with DatLab software is world-wide the only instrument (sole source) which allows routine measurements to be made with specifications summarized under the term high-resolution respirometry (HRR).

Oxygraph-2k: technical specifications

Definition of HRR


High-resolution respirometry (HRR) is defined on the basis of instrumental features of the O2k. The limit of detection of oxygen flux is as low as 1 pmol O2.s-1.ml-1. Oxygen backdiffusion at zero oxygen is <4 pmol.s-1.ml-1. Oxygen consumption by the polarographic oxygen sensor at air saturation and standard barometric pressure (100 kPa) is 2.7 ± 0.9 SD (114 test runs at 37 °C). These highly standardized instrumental background fluxes are a linear function of oxygen concentration, which is used for automatic background correction of oxygen flux (DatLab). Typical exponential time constants of the oxygen sensors are <4 s, used for dynamic corrections in kinetic studies. Signal noise at zero oxygen concentration is <0.05 µM O2.
Continuous control of the OROBOROS Oxygraph-2k specifications are a fundamental component of Quality Assurance and distinguish high-resolution respirometry from any conventional oxygraph system and from non-quantitative approaches.

»O2k versus multiwell respirometer


General specifications

  • Dimensions - O2k-Main Unit: L 45 cm, W 31 cm, H 25 cm; 14 kg without packing box or Peli Case.
  • Chambers: chemically inert and minimum oxygen diffusion:
- Two Duran glass chambers with 2 ml (1.5 to 3.5 ml) volume; 16 mm inner diameter.
- PVDF or PEEK stoppers with Viton O-rings.
- Electromagnetic stirrers with variable speed (100 to 900 rpm).
- PVDF- or PEEK-coated stirrer bars (6 mm diameter).
- Polarographic oxygen sensors (OroboPOS) sealed with butyl rubber seal tips.
  • Built-in electronically regulated Peltier thermostat:
- Temperature range:
At room temperature 4 °C to 47 °C
At lower ambient temperature 2 °C
- Temperature stability:
Temperature stability ±0.002 °C over 90 min.
- Temperature range:
in 15 min 20 °C to 30 °C
in 20 min 30 °C to 20 °C
  • Data output through USB:
- Two oxygen signals.
- Pressure transducer, for absolute barometric pressure signal, resolution 0.1 kPa.
- Thermostat temperature signal, resolution 0.001 °C.
- O2k-MultiSensor: two additional amperometric signals (O2k-fluorescence; NO sensors), and two additional potentiometric signals pX: for TPP or pH).
  • DatLab software:
- Display: simultaneous display of oxygen concentration and oxygen flux (negative slope or time derivative), together with any selected O2k-MultiSensor channels (raw or calibrated signals and corresponding time derivatives). Barometric pressure for oxygen calibration; temperature stability control.
- Automatic calibrations: oxygen and O2k-MultiSensors.


Specifications for high-resolution respirometry

  • Oxygen signal:
- Noise at zero oxygen: <0.005 kPa (SD, 100 data points recorded at 1 s intervals) without smoothing (±0.003 kPa typical)
- Noise at air saturation: <0.010 kPa (SD, 100 data points recorded at 1 s intervals) without smoothing, at partial oxygen pressure of 20 kPa (±0.005 kPa typical)
- Time constant: <7 s at 25 °C (<4 s typical)
- O2 range of linearity: Oxygen partial pressure of 0 to 100 kPa
  • Oxygen flux:
- Limit of detection: 0.5 pmol.s-1.ml-1 at steady-state over 5 min.
- Sensitivity (normoxic): <1 pmol.s-1.ml-1 at steady-state over 5 min at 20 - 40 °C.
- Sensitivity (hyperoxic): <3 pmol.s-1.ml-1 at steady-state over 5 min at 20 - 40 °C.
- Noise: <0.2 pmol.s-1.ml-1 after standard smoothing (120 s).
- O2 range of measurement: Flux measured at oxygen partial pressure up to 100 kPa and to <0.01 kPa based on DatLab analysis of oxygen kinetics (mitochondria and cells)


  • Instrumental background for linear correction over the entire oxygen range:
- O2 backdiffusion at 0 kPa:
<3 pmol.s-1.ml-1 at 20 to 40 °C (2.5 pmol.s-1.ml-1 typical)
- O2 consumption at 20 kPa:
<4 pmol.s-1.ml-1 at 37 °C (3 pmol.s-1.ml-1 typical)
<3 pmol.s-1.ml-1 at 25 °C (2 pmol.s-1.ml-1 typical).