Test Experiments on Specifications of the OROBOROS Oxygraph- O2k-Specifications. MiPNet06.05 [download pdf 786 kB; 2010-08-17]
The OROBOROS® Oxygraph-2k with DatLab software is world-wide the only instrument which allows routine measurements to be made with specifications summarized under the term high-resolution respirometry (HRR).
The limit of detection of O2 flux is as low as 1 pmol×s-1×cm-3. Signal noise at zero oxygen concentration is <0.05 µM O2. Oxygen backdiffusion at zero oxygen is <3 pmol×s-1×cm-3, and oxygen consumption 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.
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 (see FAQ).
Oxygraph-2k: Technical Specifications
General
=> Dimensions - O2k Main Unit: L 45 cm, W 31 cm, H 25 cm; 20.5 kg without packing box.
=> 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 stoppers with Viton O-rings, or titanium stoppers with titanium injection capillary and special Viton W-rings.
Electromagnetic stirrers with variable speed (100 to 900 rpm).
PVDF- or PEEK-coated stirrer bars (6 mm diameter).
Polarographic oxygen sensors sealed with butyl india rubber sleeves.
=> Built-in electronically regulated Peltier thermostat:
Temperature stability: ±0.002 °C over 90 minutes
Temperature change: 20 °C to 30 °C in 15 minutes
30 °C to 20 °C in 20 minutes
=> Data output through RS232:
Two oxygen signals.
Pressure transducer, for absolute barometric pressure signal, resolution 0.1 kPa.
Thermostat temperature signal, resolution 0.001 °C.
MultiSensor: 2 additional amperometric signals (NO), and two additional potentiometric signals (pX)
=> DatLab Software:
Simultaneous display of oxygen concentration and oxygen flux (neg. slope or time derivative)
Automatic oxygen calibration routine
MultiSensor acquisition: 2 amperometric channels for O2; two amperometric channels for NO; two potentiometric channels for pX (pH, TPP+, Ca2+); barometric pressure for oxygen calibration; temperature stability control
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.cm-3 at steady-state over 5 min.
Sensitivity: <2 pmol.s-1.cm-3 at steady-state over 5 min at 20 - 40 °C.
Noise: <0.2 pmol.s-1.cm-3 after standard smoothing.
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.cm-3 at 20 to 40 °C (2.5 pmol.s-1.cm-3 typical).
O2 Consumption at 20 kPa: <4 pmol.s-1.cm-3 at 37 °C (3 pmol.s-1.cm-3 typical).
<3 pmol.s-1.cm-3 at 25 °C (2 pmol.s-1.cm-3 typical).
