Crown ether based ion selective electrode for potentiometric determination of potassium

New synthesized crown ether was incorporated into a poly(vinylchloride) (PVC) matrix membrane. The membrane prepared was used for the construction and analytical evaluation of a potassium ion selective electrode. The optimum membrane composition and the appropriate preparation procedure, for obtaining the electrode (classical and nanoelectrode) with good characteristics were closely followed. The functional characteristics of the electrodes were established: the linear response range was between 10-1 -10-4 M for classical electrodes and 10-2 -10-6 M for nanoelectrodes. The sensitivity was 50 ΔmV/ΔpC and 20mV/ΔpC respectively. The stability and reproducibility were very good, for about 3 months. The membrane selectivity for classical electrodes was studied in the presence of the principal interfering ions: Li+, Na+, NH4+. Under specially circumstances, the electrode has also a linear response (10-1 -10-3 M) for NH4+. The ISE based on this crown ether may be used in clinical, industrial and environmental analysis.