A liquid handling apparatus comprising a multi-channel head for aspirating and dispensing a metered amount of liquid via an array of disposable tips, the multi-channel head comprising: - an array of connectors for picking up the array of disposable tips, whereby a peripheral end of each connector is provided with a seat on which an elastomeric seal is arranged that surrounds an outer circumference of the connector; - an alignment plate that is moveable in a z-direction, parallel to a centre axis of the disposable tips, which plate has a plurality of openings through which the connectors extend, and - a motor and a linear displacement mechanism, driven by the motor, for moving the alignment plate in z-direction relative to the connectors, wherein: the apparatus further comprises a controller which is programmed to control a position of the multi-channel head, such that the array of disposable tips may be attached to the array of connectors in a pick-up action, when the alignment plate is in a stop position, in which the multi-channel head is lowered relative to the disposable tips so as to insert each connector into an internal passageway of a corresponding disposable tip by an amount sufficient to bring an upper surface of a collar of the disposable tips into contact with an underside of the alignment plate, whereby said insertion deforms the elastomeric seal against the disposable tip internal passageway so as to form a sealing contact therewith that provides the sole attachment force between each disposable tip and the respective connector; characterized in that, the controller is further programmed to cause an alignment action to be performed, once the pick-up action is complete and prior to use of the disposable tips, in which the linear displacement mechanism moves the alignment plate from the stop position by a first amount, which is sufficient to close any gap between the underside of the alignment plate and the upper surface of the tip collars, which exists due to relaxation of the deformed elastomeric seals and/or due to small positional variations in z-direction when the disposable tips are picked up from a holder. - an array of connectors for picking up the array of disposable tips, whereby a peripheral end of each connector is provided with a seat on which an elastomeric seal is arranged that surrounds an outer circumference of the connector; - an alignment plate that is moveable in a z-direction, parallel to a centre axis of the disposable tips, which plate has a plurality of openings through which the connectors extend, and - a motor and a linear displacement mechanism, driven by the motor, for moving the alignment plate in z-direction relative to the connectors, the apparatus further comprises a controller which is programmed to control a position of the multi-channel head, such that the array of disposable tips may be attached to the array of connectors in a pick-up action, when the alignment plate is in a stop position, in which the multi-channel head is lowered relative to the disposable tips so as to insert each connector into an internal passageway of a corresponding disposable tip by an amount sufficient to bring an upper surface of a collar of the disposable tips into contact with an underside of the alignment plate, whereby said insertion deforms the elastomeric seal against the disposable tip internal passageway so as to form a sealing contact therewith that provides the sole attachment force between each disposable tip and the respective connector; characterized in that, the controller is further programmed to cause an alignment action to be performed, once the pick-up action is complete and prior to use of the disposable tips, in which the linear displacement mechanism moves the alignment plate from the stop position by a first amount, which is sufficient to close any gap between the underside of the alignment plate and the upper surface of the tip collars, which exists due to relaxation of the deformed elastomeric seals and/or due to small positional variations in z-direction when the disposable tips are picked up from a holder.