Patent ID: 7241369

Claim:
An electrochemical sensor, comprising a sensor housing; an ion-sensitive field effect transistor (ISFET) with a source connection (S), a drain connection (D), a front surface having an ion-sensitive surface area (IS) that is immersible in a measuring medium, and a rear surface facing away from the ion-sensitive surface area; a clamping element to clamp the ISFET with the rear surface against an end surface of the sensor housing, said clamping element having a central opening leaving the ion-sensitive surface area (IS) exposed; and a first rubber-elastic element placed against said front surface and a second rubber-elastic element placed against the rear surface, so that the ISFET is sandwiched between the first and second rubber-elastic elements; wherein the source connection (S) and the drain connection (D) are arranged in an interior space of the electrochemical sensor; wherein the clamping element has a leak-tight circular connection to the sensor housing formed by vibratory welding; and wherein at least one of said first and second rubber-elastic elements forms a leak-tight seal against penetration of the measuring medium from the ion-sensitive surface area (IS) to said source- and drain connections (S) and (D).