Strontium ion-selective electrodes based on the diamides with pyridine ring as ionophores

Poly(vinyl chloride) membrane strontium ion-selective electrodes were devel oped by using three lipophilic diamides containing pyridine ring as ionopho res. The relationship between the structure of the ionophores and the perfo rmance of these electrodes, as well as the effects of the plasticizers and additives, were investigated. The Sr2+-electrode based on N,N,N',N'-tetracy clohexyl-2,6-pyridine-bis(methyleneoxy acetamide) as neutral carrier, potas sium tetrakis (p-chlorophenyl) borate (KTpClPB) as additive, and o-nitrophe nyloctyl ether (o-NPOE) as plasticizing solvent. It exhibits excellent prop erties with a Nernstian slope of 29 mV/pSr(2+) and a linearity range or 2 x 10(-5) to 1 x 10(-2) M at 25 degrees C, K-Sr,Ba(Pot) = 2 x 10(-2). (C) 199 8 Elsevier Science B.V. All rights reserved.