A delivery system for a sensor chip includes a plurality of selectable ports arranged on a first assembly. Each of the selectable ports is in communication with a separate channel. The delivery system includes a second assembly movable in relation to the first assembly. The second assembly has a channel that is mechanically connectable to different ones of the plurality of selectable ports on the first assembly by motion of the second assembly relative to the first assembly. The delivery system includes a mechanical interface configured to engage a separate actuator so that relative motion of the first assembly and the second assembly is affected by the actuator.