Patent ID: 8246239

Claim:
A method of automatically metering and mixing liquids in a sample vessel by means of a metering needle, comprising the following steps: a) dispensing a volume of a liquid or a plurality of volumes of a plurality of liquids from a metering needle into a sample vessel, wherein the operation of dispensing the liquid or liquids from the metering needle begins when the dispensing opening of the metering needle is at a starting position, wherein said starting position is disposed in a vertical direction at a spacing from the bottom of the sample vessel, which corresponds to the maximum filling height of the sample vessel after complete dispensing of the liquid in this step or is above said filling height or at a maximum 10% there below, with respect to the spacing from the bottom of the sample vessel to the maximum filling height of the sample vessel after complete dispensing of the liquid in this step, the dispensing operation is continued while the metering needle is moved in a vertical direction downwardly in the direction of an end position, wherein said end position is in a vertical direction beneath said starting position and at a spacing relative to the bottom of the sample vessel, and the dispensing operation ends when the dispensing opening of the metering needle is at said end position; b) sucking up at least a part of the volume of liquid present in the sample vessel by means of the metering needle while the dispensing opening of the metering needle is in the end position; c) moving the metering needle in a vertical direction until the dispensing opening is at the starting position; and d) dispensing the volume of liquid which has been sucked up from the dispensing needle, wherein the dispensing operation begins when the dispensing opening of the metering needle is at the starting position, the dispensing operation is continued while the metering needle is moved in a vertical direction downwardly in the direction of the end position, and the dispensing operation ends when the dispensing opening of the metering needle is at the end position.