Conducting disposable tips provide cross-contamination-free pipetting for sensitive applications such as PCR setup. The tips are made of conducting material, allowing the BioRobot liquid-handling system to sense when the tip has come into contact with the surface of the liquid. The position of the tip is adjusted according to the liquid surface for accurate volume measurement. Disposable troughs allow all pipetting probes to access the same liquid simultaneously. This multiple-channel liquid transfer reduces the number of pipetting steps for fast processing and shorter run times.