A sampling unit to dispense a precise volume of liquid sample from a sample container in an automated analytical instrument, the sampling unit comprising - an elongated hollow sampling member extending along a longitudinal axis between first and second ends, the first end forms a sampling tip and the second end is connectable with a pump unit; the sampling member being adapted to move between a first position and a second position, and the sampling tip is adapted to be filled, in said first position, with liquid sample from the sample container through aspiration by said pump unit; - a liquid-sampling valve having a valve body comprising a flow structure with an inlet and an outlet, said flow structure including an aliquoting chamber of precise volume, the liquid-sampling valve being selectively operable in either (i) a first valve position in which the flow structure is adapted to be loaded with liquid sample through the inlet, said liquid sample is provided directly from the sampling tip in the second position of the sampling member, or (ii) a second valve position in which the flow structure is adapted to dispense the precise volume of liquid sample through the outlet, said precise volume of liquid sample being produced by said aliquoting chamber via segmenting the liquid sample loaded into the flow structure in the first valve position when said liquid-sampling valve is operated to change from the first valve position to the second valve position; characterized in that the sampling tip is adapted to discharge, in said second position, liquid sample through expelling by said pump unit; and the liquid-sampling valve further comprises, in the first valve position, a guiding channel extending through the valve body in its entirety in parallel with the longitudinal axis of said sampling member, said guiding channel being configured to allow free movement of the sampling member between said first and second positions through the valve body, and wherein the inlet of the flow structure is located, in the second valve position, within the same volume portion of the valve body that is occupied by the guiding channel in the first valve position. - an elongated hollow sampling member extending along a longitudinal axis between first and second ends, the first end forms a sampling tip and the second end is connectable with a pump unit; the sampling member being adapted to move between a first position and a second position, and the sampling tip is adapted to be filled, in said first position, with liquid sample from the sample container through aspiration by said pump unit; - a liquid-sampling valve having a valve body comprising a flow structure with an inlet and an outlet, said flow structure including an aliquoting chamber of precise volume, (i) a first valve position in which the flow structure is adapted to be loaded with liquid sample through the inlet, said liquid sample is provided directly from the sampling tip in the second position of the sampling member, or (ii) a second valve position in which the flow structure is adapted to dispense the precise volume of liquid sample through the outlet, said precise volume of liquid sample being produced by said aliquoting chamber via segmenting the liquid sample loaded into the flow structure in the first valve position when said liquid-sampling valve is operated to change from the first valve position to the second valve position;