Potentiometric sensors are devices that measure the voltage difference between two points in an electrical circuit. They are commonly used to determine the concentration of ions in a solution, making them essential in fields like chemistry and environmental monitoring. These sensors typically consist of a reference electrode and a sensing electrode, which work together to provide accurate readings. These sensors operate based on the principle of electrochemical potential, where the voltage changes in response to variations in ion concentration. Common applications include measuring pH levels in water quality testing and monitoring biochemical processes in laboratories.