Answer: The four types of ion selective electrodes are:
Glass electrodes
Solid-state electrodes
Gas-sensing electrodes
Enzyme electrodes
Explanation: The glass electrode is considered to be the ion selective electrode that is utilized most frequently in various scientific applications. The aforementioned entities are comprised of a delicate glass membrane that exhibits a sensitivity towards particular ions, namely hydrogen ions (pH), sodium ions and chloride ions. The glass membrane is coated with a slim metal layer which serves as a conductor and is imbued with a unique solution referred to as an electrolyte.