Calixazacrown ethers for copper(II) ion-selective electrode

Five novel 1,3-alternate calix[4]azacrown ethers having 2-picolyl, 3-picoly l, and benzyl unit on the nitrogen atom were synthesized and used as ionoph ores for transition metal-selective polymeric membrane electrodes. The elec trode based on 2-picolyl armed 1,3-alternate calix [4] azacrown ether exhib ited Nernstian response toward copper (II) ion over a concentration range ( 10(-4.5) M-10(-2.5) M). The detection limit was determined as 10(-5) M in p H 7 and the selectivity coefficients for possible interfering cations were evaluated. Anions in the sample solution strongly affected the electrode re sponse. (C) 2001 Elsevier Science B.V. All rights reserved.