An interface component (40), suitable for cooperating with a microfluidic device (1), the interface component comprising, one or more elements (41) which can be selectively connected to a pneumatic system (71 a,71 b) which can provide a positive and/or negative air flow to the one or more elements (41); wherein each of the one or more elements (41) comprises, an input port (42) which can be selectively fluidly connected to a pneumatic system (71 a,71 b); and a flow restrictor (43) according to a further aspect of the present invention; the flow restrictor (43) being arranged in fluid communication with the input port (42), wherein the flow restrictor (43) can restrict the flow of fluid through the element (41); and an aerosol filter (49) which is arranged to be in fluid communication with the flow restrictor (43); and wherein the interface component (40) further comprises one or more outlets (45), each of the one or more outlets (45) being in fluid communication with a respective element (41), so that fluid can flow from the element (41) out of the interface component (40) via the one or more outlets (45); and wherein each of the one or more outlets (45) can be selectively arranged to be in fluid communication with a respective reservoir (105,106,107,108) of a microfluidic device (1). There is further provided a corresponding method and assembly for extracting ferromagnetic, paramagnetic and/or diamagnetic particles from a sample.