Method and apparatus for degassing a liquid and analytical device having the apparatus

An apparatus for performing a method for degassing a liquid comprising:

• a piston pump unit comprising a receiving chamber serving for accommodating a liquid to be degassed;
• a piston movable in said receiving chamber and sealing said receiving chamber on one end;
• a liquid supply comprising the liquid to be degassed;
• at least one supply line connecting said receiving chamber with said liquid supply;
• at least a first drain, line connected with said receiving chamber;
• a valve unit, by means of which said at least one supply line and said first drain line are selectively blockable, at least at times;
• and
• a control unit configured to control the apparatus for performing the method for degassing a liquid comprising the steps:
• controlling the valve unit to block said first drain line and to connect said liquid supply via the at least one supply line with the receiving chamber and controlling the piston to perform a first stroke movement of the piston and to draw the liquid from said liquid supply via said at least one supply line into the receiving chamber;
• controlling the valve unit to block both said first drain line and said at least one supply line and controlling the piston to continue the first stroke movement in such a way, that a negative pressure is produced in the receiving chamber;
• controlling the valve unit to open said first drain line and to block said at least one supply line and controlling the piston to perform a second stroke movement in direction opposed to the first stroke movement and to remove a gas phase present in the receiving chamber from said receiving chamber via said first drain line.