Ten potassium ion selective PVC membrane electrodes based on 10 biscrown ethers [I, R1 = o-C6H4; m-C6H4; p-C6H4; 2,6-C5H3N; 1-(CH3O)C6H3-2,6-; -(CH2)2-; -(CH2)4-; -(CH2)6-; -(CH2)8-; -(CH2OCH2)-; R2 = n-C15H31] were prepared and their electrode behaviors were evaluated. Seven of these electrodes exhibited a linear response to the potassium ions within the concentration range 10-6-10-1M KCl. The low limits of linear response were 10-7-10-6M. The slopes of their calibration plots ranged from 51.6 to 60.5 mV per activity decade. These electrodes exhibited remarkable potassium ion selectivity with respect to all other alkali and alkaline earth metal cations.

Key words: AMIDES, CROWN ETHER COMPOUNDS, ION SELECTIVE ELECTRODE, POLYVINYL CHLORIDE, BENZENE P, MEMBRANE ELECTRODES, C15 COMPOUNDS