An apparatus and method for the automated preparation of treated monolayers of sample material, comprising: a
centrifuge having a rotor (12) carrying removable chamber blocks (14); sample and
reagent dispensers (26) and control systems (20). First,
centrifugal force sediments sample material discretely to form a
monolayer onto a receiving surface member (32) on one of the chamber blocks (14), while the same
centrifugal force opens a valve (48) in the chamber block (14) to drain sample material. Then,
centrifugal force delivers sequentially into discrete chamber blocks (14) discrete treating agents, during which time the sampler material
monolayer is held in place on the receiving surface member (32) by centrifugal force. Then, each chamber block (14) is drained centrifugally through its already opened valve (48). Each treated sampler material is confined to an individual chamber block (14). Batch and
random access delivery of treating agents can be employed. Each chamber block (14) includes separate inlets for the sample and treating agents.