Fabrication of Potassium Ion-selective Membrane Electrode as Immobilized Liquid based on Dibenzo-18-Crown-6 (DB18C6) as Ionophore

Precisely detection of specific ion in a solution with ion electrodes provides valuable clinical and chemical information. For this purpose, specific ion selective electrodes have been designed, which are able to detect the concentrations of specific ions as much as 10-5 M. In this study, we introduced a polyvinylchloride (PVC)–based membrane of Dibenzo-18-crown-6 (DB18C6), which exhibited good potentiometric response for K+ over a wideconcentration range of 1.0×10-5 to 1.0×10-2 mol L-1. The best Nernstian slope for the desired electrode was 53 mV/decade of K+ concentration. Matched potential method (MPM) was used for determination of selectivity coefficient. The response time for the K+ selective electrode was 30 s. The electrode was used for a period of 4 weeks. Our results showed that the electrode can be used in wide pH range from 3.0 to 9.5. Electrode was successfully applied for determination of potassium in oral rehydration salts (ORS) and mineral water.