Ion selective electrodes (ISE) also known as specific ion electrode converts specific ion into an electrical potential, which is measured by a pH meter or voltmeter. An ideal ion selective electrode consists of a thin membrane from which intended ions can be transported. Polymer membrane electrodes are based on special organic polymer membrane and are used in electrodes to measure ions such as nitrate, calcium, and potassium and gas sensing electrodes have an internal solution and gas permeable membrane. They are used in various applications for determining the concentration of various ions. Applications of ion selective electrodes in pharmaceuticals offers wide concentration range which is applicable to colored and turbid solutions. In agriculture it is used in soils, fertilizers, and plant material. It is also used in dairy products, fruit juices, drinking water, and other drinks and meat preservatives. Ion selective electrodes are simple to use, inexpensive and have an exceptional...