Lead electrodes are potentiometric devices used for the titration of sulfate with lead perchlorate. A Lead electrode may be used as an indicator to follow the progress and detect the endpoint of a precipitation titration of sulfate (with concentration >50 ppm) using lead perchlorate standard. During the titration the sensor follows the lead concentration while small additions of lead perchlorate titrant are added. The lead reacts with the sulfate ions forming a precipitate. At the stoichiometric end point, a change in mV occurs.