User talk:Sumbalova Zuzana

Closed chamber

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 cappilary. If some bubble remains in the chamber, the capillary should be relieved by inserting long needle into the cappillary. After closing the chamber the excessive liquid should be aspirated from the top of the stopper. The procedure of a bubble-free closing closing chamber with a multisensor stopper is described on page 11 of the manual for ion selective electrodes [1].

Oxygen flux in closed chamber

The oxygen flux in closed chamber at air-calibrated oxygen concentration is an important control parameter. It reflects the consumption of oxygen by polarographic oxygen sensor POS. The theoretical value is between 2 and 3 pmol.s-1.ml-1 [2]. The value higher than 4-5 pmol.s-1.ml-1 indicates a biological contamination in the chamber. Lower value indicates that the volume of the chamber is probably bigger.