This information is part of O2k-Open Support.
Closed chamber means that the chamber and the capillary of the stopper is filled with liquid and no air space or bubble is present in the chamber. For closing the chamber without a bubble an excessive amount of liquid has to be present in the chamber (2.5 ml for 2 ml chamber). The conical shape of the standard stopper facilitates bubble-free closing of the chamber with stirrers switched on - the bubbles will escape through the capillary. If some bubble remains in the chamber, the capillary should be relieved by inserting long needle into the capillary. After closing the chamber the excessive liquid should be aspirated from the top of the stopper. The procedure of bubble-free closing closing a chamber with a multisensor stopper is described in the manual for ion selective electrodes MiPNet15.03.
See also: Open chamber