Benzo-15-crown-5 as a neutral ionophore in fabrication of potentiometric sensors

Potentiometric ion selective electrodes (ISEs) are one of the most important types of chemical sensors. A significant number of ionophores, including crown ethers, cryptands, aza-crowns and thiacrowns, have been exploited for the fabrication of polyvinyl chloride (PVC) membrane electrodes for the determination of alkali, alkaline earth, transition and heavy metal ions [1-2]. Potentiometric ionophore-based membrane sensors are preferred measuring tools for a variety of applications. In fact, ion selective electrodes (ISEs) for as many as 60 analysts have been described so far [3-4]. In this project, an europium (III) selective coated graphite electrode based on benzo-15-crown-5 as a neutral carrier has been fabricated. This sensor had a linear concentration range from 1.0×10-5 to 1.0×10-1 M with a good Nernstian slope in the pH range of 3.0-12.0. The detection limit of the electrode was 4.4×10−6 M. This electrode revealed a good selectivity towards Eu3+ ion over a wide range of metal cations and a good dynamic response time was observed in the whole concentration range. Also, this sensor was successfully used for direct determination of europium (III).