Application of Ionic Liquid to the Construction of Cu(II) ion-selective Electrode with Solid Contact

Potentiometric properties of copper ion-selective electrodes (ISEs) with solid contact based on polymeric membrane were investigated. For the electrode construction ionic liquids (ILs), alkylmethylimidazolium chlorides are used as transducer media. The addition of ionic liquid to the membrane phase was found to improve the analytical parameters of the studied electrodes. The best results were obtained for electrode having membrane doped with 1-ethyl-3-methyl imidazolium chloride. The electrode shows a Nernstian response for copper ions over a wide concentration range (1x10-7-1x10-1 mol L-1) and the slope of 28.9 mV/decade. The limit of detection is 3.2x10-8 mol L-1. It has a fast response time of 5-10 s and can be used for more than 4 months without any divergence in potential. The proposed sensor is not pH sensitive in the range 2.5-6.0 and shows a very good discriminating ability towards Cu2+ ion in comparison with some alkali, alkaline earth, transition and heavy metal ions.