A method for aspirating and dispensing a liquid sample in an automated analytical instrument, said method comprising using an apparatus comprising: (a) an aspiration probe (AP), operably connected to a pump , and adapted to enter a sample container (C) to aspirate a liquid sample within such container (C); (b) a transport system for selectively advancing the aspiration probe (AP) in mutually perpendicular planes so that said aspiration probe (AP) can aspirate or dispense liquid from or to different containers (C) spaced apart; and (c) a liquid-sampling valve (LSV), operatively connected between said aspiration probe (AP) and pump , and comprising structure defining at least one aliquoting chamber (S1;S2) for temporarily storing a precise volume of liquid sample to be dispensed; the method comprising operating the pump selectively to either (i) draw a liquid sample through said aspiration probe (AP) and through the liquid-sampling valve (LSV) to fill said aliquoting chamber (S1;S2), or (ii) to dispense an already aspirated liquid sample through said liquid-sampling valve (LSV) and through said aspiration probe (AP); said method further comprising operating the liquid-sampling valve (LSV) selectively in either (i) a loading configuration in which the liquid sample aspirated by the aspiration probe (AP) under the influence of the pump will pass through the liquid-sampling valve (LSV) while simultaneously filling said aliquoting chamber (S1 ;S2) thereof, or (ii) a segmenting/dispensing configuration in which the liquid sample within said aliquoting chamber (S1;S2) is positioned to be dispensed from said liquid-sampling valve (LSV) to a reaction chamber (RC1, RC2) by a force external to the liquid sampling valve, while said pump operates in a suck-and-spit mode aspirating a liquid sample from a sample container (C) and dispensing an already aspirated liquid sample to a reaction chamber (RC3, RC4) through said aspiration probe (AP) and through said liquid-sampling valve (LSV). (a) an aspiration probe (AP), operably connected to a pump , and adapted to enter a sample container (C) to aspirate a liquid sample within such container (C); (b) a transport system for selectively advancing the aspiration probe (AP) in mutually perpendicular planes so that said aspiration probe (AP) can aspirate or dispense liquid from or to different containers (C) spaced apart; and (c) a liquid-sampling valve (LSV), operatively connected between said aspiration probe (AP) and pump , and comprising structure defining at least one aliquoting chamber (S1;S2) for temporarily storing a precise volume of liquid sample to be dispensed; the method comprising operating the pump selectively to either (i) draw a liquid sample through said aspiration probe (AP) and through the liquid-sampling valve (LSV) to fill said aliquoting chamber (S1;S2), or (ii) to dispense an already aspirated liquid sample through said liquid-sampling valve (LSV) and through said aspiration probe (AP); said method further comprising operating the liquid-sampling valve (LSV) selectively in either (i) a loading configuration in which the liquid sample aspirated by the aspiration probe (AP) under the influence of the pump will pass through the liquid-sampling valve (LSV) while simultaneously filling said aliquoting chamber (S1 ;S2) thereof, or (ii) a segmenting/dispensing configuration in which the liquid sample within said aliquoting chamber (S1;S2) is positioned to be dispensed from said liquid-sampling valve (LSV) to a reaction chamber (RC1, RC2) by a force external to the liquid sampling valve, while said pump operates in a suck-and-spit mode aspirating a liquid sample from a sample container (C) and dispensing an already aspirated liquid sample to a reaction chamber (RC3, RC4) through said aspiration probe (AP) and through said liquid-sampling valve (LSV). <EOS>