Abstract: A potentiometric sensor apparatus, comprising: a measuring half-cell having a measuring membrane; a reference half-cell; and a measurement circuit for registering a potential difference between the measuring half-cell and the reference half-cell. The measuring membrane has, covering at least one portion of the measuring membrane during dry storage of the sensor apparatus, a coating, which is embodied, upon immersion of at least one immersion region of the sensor apparatus (which region comprises the measuring membrane and is intended for immersion in a measured medium) in a liquid, especially a water containing liquid, in the case of continued contact with the liquid, to dissolve, at least partially, off of the measuring membrane.

Abstract: An arrangement for optical measurement of at least one process variable in a medium, comprising: at least one light source; at least one light receiver; an optical sensor element at least one data processing unit; and a light conductor. The light conductor connects the light source with the optical sensor element and the optical sensor element with the light receiver. The light conductor is embodied with at least three arms, wherein the first arm is arranged at the light source, the second arm is arranged at the light receiver and the third arm is arranged at the optical sensor element first arm and the second arm combine to form the third arm. The invention relates further to a measuring device comprising an above described arrangement.

Abstract: A measuring membrane for an optochemical or amperometric sensor for determining or monitoring an analyte located in a medium, comprising a substrate material and a sensor element, which has at least one functional layer with a sensor-specific substance. The sensor element is embedded completely in a matrix, and the matrix is composed of a material, which at least in a portion facing the medium and adjoining the sensor element is permeable for the analyte.

Abstract: An arrangement for optical measurement of at least one process variable in a medium, comprising: at least one light source; at least one light receiver; an optical sensor element at least one data processing unit; and a light conductor. The light conductor connects the light source with the optical sensor element and the optical sensor element with the light receiver. The light conductor is embodied with at least three arms, wherein the first arm is arranged at the light source, the second arm is arranged at the light receiver and the third arm is arranged at the optical sensor element first arm and the second arm combine to form the third arm. The invention relates further to a measuring device comprising an above described arrangement.