The present disclosure relates to an ion-selective half-cell comprising a carrier that extends in a sleeve-like manner along an axis and has a first open end and a second end opposite the first open end, an insert that extends in a sleeve-like manner along the axis and is arranged in the first open end, a membrane that is arranged in the first open end and at least partially in the insert in such a way that the first open end is closed by the membrane, an electrolyte that is arranged in the carrier and is in electrolytic contact with the membrane, and a lead that is arranged in the carrier and is in electrical contact with the electrolyte.