Abstract: A device and method for detecting and quantifying a substance by filtration. The device includes a body having two parts (1 and 2) nested into each other. One of the parts (1) is used as a reservoir and the other part (2) is used as a filter-holder and as a receptacle. The device further includes a retention and reaction system including a strut (3), two multi-pierced or perforated plates (4 and 5) which encase a filtering member and a thin strut. A seal is further provided between the two parts. The reservoir and the receptacle are connected to an external circuit by means of conduits, mouthpieces and pipes. The interlocking of the two parts is achieved by means of jointed hooks.