Comparative study of carbon paste electrodes modified by new pentaaza macrocyclic ligands and gold nanoparticles embedded in three-dimensional sol-gel network for determination of trace amounts of Ag(I)

摘要

Two new Ag(I) chemically modified carbon paste electrodes were prepared with comparative potentiomet-ric study of 1,3,6,10,13-pentaaza-2,14-(2,6-pyridyl)-cyclote-tradecane-4,12-dione (PPCT) and 1,3,6,9,11,12-pentaaza-2,13-(2,6-pyridyle)-bicycle[2,2,9]pentadecane-4,11-dione (PPBP) as ionophore. These sensors have been modified with sol-gel-Au nanoparticles to obtain a wide concentration range for potentiometric determination of Ag(I) in aqueous solutions. The sensors exhibit significantly enhanced selectivity toward Ag(I) ions over a wide concentration range of 4.0 x 10~(-9)-2.2 x 10~(-2) and 2.2 x 10~(-7)-2.0 x 10~(-2) mol L~(-1) with a lower detection limit of 2.5 x 10~(-9) and 2.0 x 10~(-7) mol L~(-1) for PPCT and PPBP modified electrodes respectively. The electrodes are highly selective to Ag(I) ions over a large number of mono, bi, and tri-valent cations. These electrodes were successfully used as indicator electrode for potentiometric determination of silver in sul-phadiazine (burning cream) and radiological film.