Closed chamber

From Bioblast


O2k-Open Support

Closed chamber

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


The O2k-chamber can be used as a closed system or open system. Gas bubbles must be avoided.

Abbreviation: C

Reference: System, MiPNet22.11 O2k-FluoRespirometer manual, MiPNet24.14 O2k-sV-Module manual

Application in HRR

Closed chamber means that the experimental chamber and the capillary of the stopper are filled with liquid and no air space or bubble is present in the chamber with the stopper fully inserted into the volume-calibrated position. Any titrations are performed between closed states, but not during a closed state. For closing the chamber without a gas bubble, an excessive volume of liquid has to be present in the chamber (minimum 2.1 mL for the 2-mL chamber; 0.54 mL for the 0.5-mL chamber). The stirrer can be switched on. Any foam should be avoided. Before inserting the stopper, the capillary of the stopper must be free of aqueous medium. The conical shape of the standard stopper facilitates bubble-free closing of the chamber with stirrers switched on - the bubbles escape through the central capillary. After closing the chamber the excessive liquid must be aspirated from the receptacle of the stopper.
The procedure of bubble-free closing a chamber with a multisensor stopper is described in the manual for ion selective electrodes MiPNet15.03.


Close C: Defining an event C as 'closing the chamber' is simple and understandable. But is it understood by a critical mind? A stopper inserted at any position when the O-ring engages with the glass chamber may be considered to close the chamber. Thus the stopper moved slightly up into the stopper-spacer-defined 'open' position technically still maintains the chamber as a closed system with a new volume and a combination of aqueous and gaseous phases. On the other hand, after closing the chamber (marked by C in DatLab), the chamber may be operated as a closed system (the typical mode of operation between titrations in SUIT protocols). But the fact that mass transfer is possible by titrations into the chamber defines the chamber as an open system. Steady-state injections by the TIP-2k are a paradigm of operating the O2k in a continuous open-system mode of operation. Thus the meaning of C may be (or certainly is) ambiguous and thus potentially misleading.
C should stand for "stopper in volume-Calibrated experimental position".
» Compare: Open chamber



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Quality management

Oroboros quality management from the O2k to NextGen-O2k
Gnaiger Erich 2020-09-07

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