Abstract: A pipetting head for a liquid dispensing apparatus has a pipette tip connection mechanism and a plunger clamping mechanism having a plurality of mounts for holding the plungers of the array of pipettes during use, a plurality of clamping rods, each extending inside one of the mounts, and a clamping drive mechanism operable to drive relative movement between the mounts and the clamping rods to selectively engage the clamping mechanism. The mounts each have a radially extending feature configured to form one half of a snap-fit connection. The clamping region of each of the clamping rods is axially adjacent to the radially extending feature of its associated mount when in a clamping position, and is axially offset from the radially extending feature of its associated mount when in the release position. The clamping rod prevents the snap-fit connection with the plunger from being released when in the clamping position.