Benzo15-crown-5 as sensory molecule for fabrication of a lead(II) ion-selective potentiometric sensor

Benzo15-crown-5 (b15c5) has been examined as an ion sensing material for fabricating a pvc membrane lead ion-selective potentiometric sensor. the best performance of the electrode was observed with a membrane composition formed by 29% pvc, 60% dibutylphthalate (dbp) as plasticizing solvent mediator, 2% sodium tetraphenylborate (natpb) as ion excluder and 9% of b15c5 as ionophore. the electrode presents a nearly nernstian response (a slope of 29.7±0.5 mv/decade) over a concentration range 1×10-5-1×10- 3 m of lead ions, with a limit of detection 8.4×10-6 m. its potential response was independent on ph variation in the range 2.8-4.5. the dynamic response time of the electrode to achieve a steady potential was found to be about 25 seconds. the selectivity of the prepared electrode relative to some mono-, di-, tri- and tetra-valent metal ions was examined. this electrode can be used for 2 months without considerable divergences in the potential response. it was successfully used as an indicator electrode for the complex formation titration of lead inwater sampless by edta.