Iodide recognition by the N,N-bis-succinamide-based dendritic molecule [CH2C(O)NHC(CH2CH2C(O)OtBu)3]2

Ion selective membrane electrode doped with amide functionalized dendritic [CH2C(O)NHC(CH2CH2C(O)OtBu)(3)](2) macromolecule was evaluated as anion sensor. The ability of the membrane has been explored by incorporating it into a plasticized PVC matrix on glassy carbon electrode. The effects of membrane composition, pH and the influence of anion additives, and also the nature of the plasticizers on the response characteristics of the electrode were investigated. The resulting electrode exhibits an anti-Hofmeister selectivity pattern with remarkable specificity towards iodide over other lipophilic inorganic anions. The optimum membrane composition for best potentiometric performance was achieved with a DPE-plasticized membrane (DPE=diphenyl ether) doped with 15%TBAB (TBAB = tetrabutyl ammonium bromide), suggesting that the ionophore operates via a neutral carrier mechanism. It has a linear response to iodide with a detection limit of 4.46 x 10(-7) M and a slope of 59.6 mV/decade, a satisfactory reproducibility and a rapid response time. The selectivity coefficients for I- towards interferences from ClO4-, NO3- and Cl- were estimated to be K-Ranion(pot) = 1.25 x 10(-4), 1.99 x 10(-4) and 7.94 x 10(-5), respectively. Application of the electrode to the potentiometric titration of iodide ion with silver nitrate is also reported. (C) 2008 Elsevier B.V. All rights reserved.