Device with disposable element

A connector comprising:

• a reusable component comprising a retention groove and an electrical contact surface that is parallel to the retention groove;
• and
• a detachable element comprising:
• a body with a retention feature configured to engage the retention groove and an electrical contactor coupled to the body, wherein the contactor comprises a compliant element that is configured to touch the contact surface of the reusable element when the retention feature of the detachable element is engaged with the retention groove of the reusable component and to slide along the contact surface as the detachable element is brought together with the reusable component, and
• a sensor comprising two electrodes, wherein the two electrodes consist of one central electrode and one toroidal electrode, and wherein the central electrode and the toroidal electrode have a concentric orientation.