The present invention relates to a filter apparatus (1) for use in an automated system (100) for the preparation of a fluid sample for a chemical or composition analysis. The filter apparatus (1) comprises an inlet portion (2) with a conduit (3) ending in an entry port (4) for receiving the sample in an unfiltered state； a septum (5) held at and closing the entry port (4) of the conduit (3) of the inlet portion (2)； an outlet portion (6) with a channel (7) for dispensing the filtered sample to a receptacle (70)； and an intermediate portion (8) having a filter chamber (9) in fluid connection with the conduit (3) of the inlet portion (2) and with the channel (7) of the outlet portion (6) and a filter layer (10). The filter chamber (9) of the intermediate portion (8) has a diameter larger than a diameter of the conduit (3) of the inlet portion (2) and than a diameter of the channel (7) of the outlet portion (6). The filter layer (10) extends through the filter chamber (9) such that the conduit (3) of the inlet portion (2) is separated from the channel (7) of the outlet portion (6) by the filter layer (10). The present invention also deals with an automated system (100) for the preparation of a sample for a chemical or composition analysis and with a correlated method of preparing such a sample. The automated system (100) comprises an injection head (50) for the injection of an amount of sample in a receptacle (70) and a filter apparatus (1) as above introduced. The injection head (50) is equipped with a needle (51) adapted to be affixed to the filter apparatus (1) by piercing a septum (5) of the filter apparatus (1).La présente invention concerne un appareil de filtration (1) pour l'utilisation dans un système automatisé (100) pour la préparation d'un échantillon de liquide pour une analyse chimique ou de composition. L'appareil de filtration (1) comprend une partie orifice d'entrée (2) avec un conduit (3) se terminant dans un orifice d'entrée (4) pour recevoir l'échan
