An Ion Selective Electrode (ISE) is a type of sensor used to measure the concentration of specific ions in a solution. It works by generating a voltage that is proportional to the ion activity, allowing for precise analysis of various substances, such as sodium, potassium, or chloride ions. ISEs are widely used in laboratories, environmental monitoring, and clinical applications. The electrode consists of a selective membrane that responds to the target ion while excluding others. This membrane can be made from various materials, including glass or polymer, depending on the ion being measured. ISEs are essential tools in fields like chemistry, biology, and water quality testing.