Abstract: A flow apparatus for detecting a component on a surface is provided. The flow apparatus, comprising an inlet for receiving a solution of the components to be detected; a detection chamber in fluid connection with and downstream from the inlet, and in fluid connection with a downstream outlet, wherein the internal surface of the detection chamber comprises a plurality of detection zones and the detection zones are configured to adhere to the component to be detected such that the component is immobilised in the detection zones; a detector for detecting components immobilised on each of the detection zones; and a director for directing the flow of the solution of the components to each of the detection zones in sequence, wherein the director is provided by flow rates.