Device hermetically sealing a filtering system

A device covering in suction-proof, i.e. hermetic manner a filtering system that includes, in the form of one flat composite structure, jointly manufactured reaction vials. Each of the reaction vials have an upper aperture and a lower aperture, with the, upper apertures being situated substantially in an upper surface of the filtering system. The, device is fitted with a resiliently deforming mat that may be mounted flat on the filtering system, only the reaction vials situated in a partial surface zone of the filtering system being hermetically covered when the mat is mounted on the upper filtering system surface. The mat is mounted flat on the underside of a rigid plate having dimensions matching the upper surface of the filtering system. The mat is designed in a manner such that, when the plate is mounted on the top surface of the filtering system, the mat sealingly engages both upper wall regions of the upper apertures and/or the regions of the filtering system surrounding the upper apertures such that no air can flow between the mat and the filtering system between the apertures when vacuum is applied to the lower apertures.