| Abstract: | An ion‐selective electrode using ionophore 2′‐picolyl sym‐dibenzo‐16‐crown‐5 ether as membrane carrier, sodium tetraphenylborate (NaTPB) as an anion excluder, and 2‐nitrophenyl‐octyl ether (NOPE) as the plasticing solvent mediator has been successfully developed. This electrode exhibits al in ear response with a slope of 42 mV/decade in concentration ranging from 10?5 molL?1 to 10?1 molL?1, slightly larger than the 30 mV expected from the one‐to‐one complex. The reason for the super‐Nernstain slope is the partial dimmer formation in side the membrane of the electrode, because this dimmer Cu(C25H27NO6)2(H2O)2] 2ClO4, has been isolated and confirmed by single crystal X‐ray crystallography. The detection limit for the cop per (II) ion was estimated to be 1 × 10?6 molL?1. Electrades composed of other plasticing solvent mediators such as tris(2‐ethylhexyl) phosphate (TOP), bis (2‐ethylhexyl) sebacate (DOS) and dibutyl phthalate (DBP) were also investigated. Stability constants (logKs) of the two to one and the one to one 2‐picolylsym‐dibenzo‐16‐crown‐5 ether‐Cu (II) complexes have been determined by potentiometric titration in methanol. |
