Abstract: An apparatus for automatically establishing fluid communication between a probe and a plurality of containers presented in the sequence to a sampling position includes a container supported rack movable into and out of the sampling position. A probe holder supports the probe for movement into and out of the sampling position. A drive unit connects to the rack and probe holder for effecting and controlling the movements thereof. The drive unit includes a first pressure fluid operated motor actuable for moving the probe into and out of the sampling position for communication with a container thereat and a second pressure fluid operated motor actuable for causing the rack to move a desired one of the containers into the sampling position, the first and second pressure fluid operated motors being actuable independently of each other from a common source of pressure fluid. The apparatus is connectible to provide sequential samples for an analysis system, such as a high pressure liquid chromatography system.