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| 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).
| | #REDIRECT [[MiPNet06.05 Test Experiments on O2k-Specifications]] |
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| == HRR ==
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| The limit of detection of oxygen flux is as low as 1 pmol O2.s-1.ml-1.Β Β 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 Β± 0.9 SD (114 test runs at 37 Β°C).Β These highly standardized instrumental background fluxes are a linear function of oxygen concentration, which is used for automatic background correction of oxygen flux (DatLab).Β 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 Β΅M O2.
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| 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.
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| == Oxygraph-2k: technical specifications ==
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| === General ===
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| * Dimensions - O2k-Main Unit: L 45 cm, W 31 cm, H 25 cm; 14 kg without packing box or Peli Case.
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| * Chambers: chemically inert and minimum oxygen diffusion:
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| ::: - Two Duran glass chambers with 2 ml (1.5 to 3.5 ml) volume; 16 mm inner diameter.
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| ::: - PVDF or PEEK stoppers with Viton O-rings.
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| ::: - Electromagnetic stirrers with variable speed (100 to 900 rpm).
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| ::: - PVDF- or PEEK-coated stirrer bars (6 mm diameter).
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| ::: - Polarographic oxygen sensors (OroboPOS) sealed with butyl rubber seal tips.
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| * Built-in electronically regulated Peltier thermostat:
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| ::: - Temperature range:
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| :::::{| class="wikitable"
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| | At room temperature
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| | 4 Β°C to 47 Β°CΒ
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| | At lower ambient temperature
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| | 2 Β°C
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| ::: - Temperature stability:
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| :::::{| class="wikitable"
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| | Temperature stability
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| | Β±0.002 Β°C over 90 min.
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| ::: - Temperature range:
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| :::::{| class="wikitable"
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| | in 15 min
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| | 20 Β°C to 30 Β°CΒ
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| | in 20 min
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| | 30 Β°C to 20 Β°C
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| * Data output through USB:
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| ::: - Two oxygen signals.
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| ::: - Pressure transducer, for absolute barometric pressure signal, resolution 0.1 kPa.
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| ::: - Thermostat temperature signal, resolution 0.001 Β°C.
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| ::: - O2k-MultiSensor: two additional amperometric signals (O2k-fluorescence; NO sensors), and two additional potentiometric signals pX: for TPP or pH).
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| *DatLab software:
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| ::: - 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.
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| ::: - Automatic calibrations: oxygen and O2k-MultiSensors.
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| === Specifications for high-resolution respirometry ===
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| * Oxygen signal:
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| ::: - Noise at zero oxygen: <0.005 kPa (SD, 100 data points recorded at 1 s intervals) without smoothing (Β±0.003 kPa typical)
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| ::: - 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 (Β±0.005 kPa typical)
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| ::: - Time constant: <7 s at 25 Β°C (<4 s typical)
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| ::: - O2 range of linearity: Oxygen partial pressure of 0 to 100 kPa
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| * Oxygen flux:
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| ::: - Limit of detection: 0.5 pmol.s-1.ml-1 at steady-state over 5 min.
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| ::: - Sensitivity (normoxic): <1 pmol.s-1.ml-1 at steady-state over 5 min at 20 - 40 Β°C.
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| ::: - Sensitivity (hyperoxic): <3 pmol.s-1.ml-1 at steady-state over 5 min at 20 - 40 Β°C.
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| ::: - Noise: <0.2 pmol.s-1.ml-1 after standard smoothing (120 s).
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| ::: - 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)
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| * Instrumental background for linear correction over the entire oxygen range:
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| ::: - O2 backdiffusion at 0 kPa:
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| ::::::::: <3 pmol.s-1.ml-1 at 20 to 40 Β°C (2.5 pmol.s-1.ml-1 typical)
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| ::: - O2 consumption at 20 kPa:
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| ::::::::: <4 pmol.s-1.ml-1 at 37 Β°C (3 pmol.s-1.ml-1 typical)
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| ::::::::: <3 pmol.s-1.ml-1 at 25 Β°C (2 pmol.s-1.ml-1 typical).
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