The aim of this research is to focus on trace level analysis of metal ions in our environment. Pollution caused by metal ions is of big concern in the present scenario especially in the developing countries. This Book highlights a low- cost approach for metal ion sensing of liquid membrane based Potentiometric Sensors. Amide based ionophores and macrocycles containing heteroatoms are used as a sensing material during the fabrication of the sensors. All sensors exhibit wide measuring range, low detection limit, appreciable life time, and good selectivity behavior towards target metal ion even in the non aqueous medium. They can also be used as an indicator electrode for the testing of trace amount of metal ions over real life samples.