engleski

Analysis of copper-silver sulfide based Cu(II)-ISE in sea water

In view of toxic effects of copper, it`s determination in environmental samples especially in sea water (chloride media) is thus important. The Cu ion-selective electrode (ISE) offers an atractive methode for determination of Cu in natural media. Copper selective electrodes are usually based on mixed metal sulfides such as copper sulfides and silver sulfide. Different preparation conditions lead to the different electrochemical characteristic (e.g. conductivity, ...) of electroactive material incorporated in ion-selective membrane. However, mesurement of concentration of copper(II) ion is limited in a complex media such as sea water owing to chloride concentration in sea water. An conventional ISE electric contact between membrane and inner reference electrode is provided through inner reference solution. This contact show some disadvantages in view of handling and withstanding at high temperature and pressure. Direct contact of membrane with metal plate (solid contact) offer a solution of these problems. Mixed sulfides were prepared with different ratio of sodium sulfide and copper(II) nitrate gave a different electrochemical properties which is analysed by impedance spectroscopy and cyclic voltammetry. Also different behaviour, concerning potentiometric reponse in chloride media, was detected. Figure: potentiometric response of membranes preparied with different ratio of sodium sulfide and copper(II) nitrate in 0.5 M KCl.

ionophore; copper(II); ion selective; potentiometry

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