Single-piece all-solid-state Co(II) ion-selective electrode for cobalt monitoring in real samples

Abstract

A novel single-piece all-solid-state ion-selective electrode for Co2+ determination has been prepared. The PVC membrane was modified by the addition of ionic liquid. The effect of various ionic liquids was studied in detail and improved performance was observed. The best performance exhibited by the electrode was achieved with a membrane containing 1-ethyl- 3-methyl imidazolium chloride, having a slope of 31.8 mV/decade in a wide concentration range of 1×10-7 - 1×x10-1 mol L-1. The limit of detection was 5.6×10-8 mol L-1. The response time of the proposed sensor was less than 10 s and the lifetime was at least three months. The proposed sensor showed good selectivity towards the Co2+ ion in comparison with some alkali, alkaline earth, transition and heavy metal ions. It was successfully applied for the direct determination of cobalt ions in real sample solution.