The invention relates to a device for receiving a fluid sample, which is designed such as to form an electrode, such as a counter electrode or a working electrode, in an electrochemical cell. The inventive device comprises an end part having at least one cavity which opens to the exterior via an opening and which is equipped with a base. The invention is characterized in that the aforementioned end part comprises a first electrically-insulating hydrophobic zone which is adjacent to the cavity opening and a second electrically-conducting hydrophilic zone which is adjacent to the first zone and which at least partially covers the base of the cavity, such that, when the end part is immersed in the fluid and then removed therefrom, the cavity retains part of the fluid by means of capillary action.