A sulfur concentration detection system for detecting a sulfur concentration in a liquid includes a sensor having a conductive metal substrate and zinc oxide microstructures deposited on and protruding from the conductive metal substrate, a current source, and a voltage detector. An electrical resistivity of the zinc oxide microstructures is configured to change as a function of an amount of sulfur in the liquid available to react with zinc in the zinc oxide microstructures. The current source and the voltage detector are connected to the conductive metal substrate and configured to detect a change in the electrical resistivity of the zinc oxide microstructures.