A sensing system includes a sensor and one or more processors. The sensor includes a sensing region in contact with an industrial fluid. The sensing region includes electrodes and a sensing region circuit electrically connected to the electrodes. The sensing region circuit generates an electrical stimulus having multiple different frequencies that are applied to the industrial fluid via the electrodes. The one or more processors receive one or more electrical signals from the sensor representative of an impedance response of the sensing region to the electrical stimulus. The one or more processors analyze the impedance response and determine at least one of a contaminant concentration of an external contaminant in the industrial fluid, an acid concentration of acidic components in the industrial fluid, or a base concentration of basic components in the industrial fluid based on the impedance response.