Method and apparatus for the metered dispensing of liquid amounts in the range from 0.1 nl to 100 mul

According to the prior art, the smallest quantities of liquids were dosed by means of electromagnetic valves functioning as pumps or by means of micropumps operated by actuators. These technologies are uneconomical, among other things, since effective cleaning of the systems is problematic which often leads to failure of the entire system. Furthermore, the systems are not capable of dosing when air bubbles which are nearly impossible to prevent are present in the liquid channels. According to the invention, the dosing of liquid is controlled by a gas surge. A gas surge is conducted through a gas line (6) that is connected to the capillaries (5a, b). A quantity (V) of liquid located in a section of the capillaries (5b) is dosed by means of this gas surge. This is advantageous in that the gas surge is only applied to the volume (V) that should also be dosed. The liquids are dosed in quantities ranging from 0.1 nl to 100 mu l.