A sensor for measuring electrochemical impedance includes a primary circuit that includes a primary electrically conducting coil and a secondary circuit that includes a secondary electrically conducting coil. The primary electrically conducting coil is inductively coupled to the secondary circuit. During operation, the secondary electrically conductive couple has contact electrodes that contact a medium for which the impedance is to be measured. An alternating current source energizes the primary electrically conducting coil during impedance measurements.