An apparatus includes a frame configured to hold sample holders in an array, a longitudinal axis of the sample holder extending outward of an array plane; a drive section connected to the frame; at least one transfer arm rotatably connected to the drive section so that each transfer arm rotates about a rotation axis oriented substantially parallel with the longitudinal axis and includes a sample holder gripper; and at least one push member movably connected to the drive section and being distinct from the sample holder gripper and configured for linear movement along the longitudinal axis, the at least one push member being configured so that engagement with at least a bottom or top surface of the sample holder effects longitudinal translation of the sample holder for one or more of capture and release of the sample holder by the respective transfer arm in the longitudinal direction.