A measurement system is disclosed for determining a sulfur concentration in a liquid, such as a liquid fuel. The measurement system includes a first electrode that is at least partially coated with zinc oxide and, more specifically, zinc oxide microstructures. The zinc oxide microstructures have a crystal lattice structure that is oriented in the (002) plane. The first electrode may be connected to an electrometer which, in turn, may be connected to a second electrode. The second electrode may be disposed on a common substrate with the first electrode or may be in the form of a plate disposed substantially parallel to the first electrode.